diff --git a/homeassistant/components/mqtt/__init__.py b/homeassistant/components/mqtt/__init__.py
index a0527cfe427..81c44ac8aea 100644
--- a/homeassistant/components/mqtt/__init__.py
+++ b/homeassistant/components/mqtt/__init__.py
@@ -44,6 +44,7 @@ from . import config_flow  # noqa: F401 pylint: disable=unused-import
 from . import debug_info, discovery
 from .const import (
     ATTR_DISCOVERY_HASH,
+    ATTR_DISCOVERY_PAYLOAD,
     ATTR_DISCOVERY_TOPIC,
     ATTR_PAYLOAD,
     ATTR_QOS,
@@ -1169,6 +1170,7 @@ class MqttDiscoveryUpdate(Entity):
             _LOGGER.info(
                 "Got update for entity with hash: %s '%s'", discovery_hash, payload,
             )
+            old_payload = self._discovery_data[ATTR_DISCOVERY_PAYLOAD]
             debug_info.update_entity_discovery_data(self.hass, payload, self.entity_id)
             if not payload:
                 # Empty payload: Remove component
@@ -1176,9 +1178,13 @@ class MqttDiscoveryUpdate(Entity):
                 self._cleanup_discovery_on_remove()
                 await _async_remove_state_and_registry_entry(self)
             elif self._discovery_update:
-                # Non-empty payload: Notify component
-                _LOGGER.info("Updating component: %s", self.entity_id)
-                await self._discovery_update(payload)
+                if old_payload != self._discovery_data[ATTR_DISCOVERY_PAYLOAD]:
+                    # Non-empty, changed payload: Notify component
+                    _LOGGER.info("Updating component: %s", self.entity_id)
+                    await self._discovery_update(payload)
+                else:
+                    # Non-empty, unchanged payload: Ignore to avoid changing states
+                    _LOGGER.info("Ignoring unchanged update for: %s", self.entity_id)
 
         if discovery_hash:
             debug_info.add_entity_discovery_data(
diff --git a/homeassistant/components/mqtt/binary_sensor.py b/homeassistant/components/mqtt/binary_sensor.py
index cd69967e6a7..5d69bfde4f6 100644
--- a/homeassistant/components/mqtt/binary_sensor.py
+++ b/homeassistant/components/mqtt/binary_sensor.py
@@ -169,7 +169,8 @@ class MqttBinarySensor(
 
             if expire_after is not None and expire_after > 0:
 
-                # When expire_after is set, and we receive a message, assume device is not expired since it has to be to receive the message
+                # When expire_after is set, and we receive a message, assume device is
+                # not expired since it has to be to receive the message
                 self._expired = False
 
                 # Reset old trigger
diff --git a/homeassistant/components/mqtt/light/schema_template.py b/homeassistant/components/mqtt/light/schema_template.py
index a9f18e7039b..d14cda70bb6 100644
--- a/homeassistant/components/mqtt/light/schema_template.py
+++ b/homeassistant/components/mqtt/light/schema_template.py
@@ -101,10 +101,10 @@ async def async_setup_entity_template(
     config, async_add_entities, config_entry, discovery_data
 ):
     """Set up a MQTT Template light."""
-    async_add_entities([MqttTemplate(config, config_entry, discovery_data)])
+    async_add_entities([MqttLightTemplate(config, config_entry, discovery_data)])
 
 
-class MqttTemplate(
+class MqttLightTemplate(
     MqttAttributes,
     MqttAvailability,
     MqttDiscoveryUpdate,
diff --git a/tests/components/mqtt/test_alarm_control_panel.py b/tests/components/mqtt/test_alarm_control_panel.py
index aa6452fd9c8..734e1fd552f 100644
--- a/tests/components/mqtt/test_alarm_control_panel.py
+++ b/tests/components/mqtt/test_alarm_control_panel.py
@@ -28,6 +28,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -42,6 +43,7 @@ from .test_common import (
     help_test_update_with_json_attrs_not_dict,
 )
 
+from tests.async_mock import patch
 from tests.common import assert_setup_component, async_fire_mqtt_message
 from tests.components.alarm_control_panel import common
 
@@ -575,6 +577,20 @@ async def test_discovery_update_alarm(hass, mqtt_mock, caplog):
     )
 
 
+async def test_discovery_update_unchanged_alarm(hass, mqtt_mock, caplog):
+    """Test update of discovered alarm_control_panel."""
+    config1 = copy.deepcopy(DEFAULT_CONFIG[alarm_control_panel.DOMAIN])
+    config1["name"] = "Beer"
+
+    data1 = json.dumps(config1)
+    with patch(
+        "homeassistant.components.mqtt.alarm_control_panel.MqttAlarm.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, alarm_control_panel.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
diff --git a/tests/components/mqtt/test_binary_sensor.py b/tests/components/mqtt/test_binary_sensor.py
index b909a0592e0..c739f4378d1 100644
--- a/tests/components/mqtt/test_binary_sensor.py
+++ b/tests/components/mqtt/test_binary_sensor.py
@@ -26,6 +26,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -593,6 +594,20 @@ async def test_discovery_update_binary_sensor(hass, mqtt_mock, caplog):
     )
 
 
+async def test_discovery_update_unchanged_binary_sensor(hass, mqtt_mock, caplog):
+    """Test update of discovered binary_sensor."""
+    config1 = copy.deepcopy(DEFAULT_CONFIG[binary_sensor.DOMAIN])
+    config1["name"] = "Beer"
+
+    data1 = json.dumps(config1)
+    with patch(
+        "homeassistant.components.mqtt.binary_sensor.MqttBinarySensor.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, binary_sensor.DOMAIN, data1, discovery_update
+        )
+
+
 async def test_expiration_on_discovery_and_discovery_update_of_binary_sensor(
     hass, mqtt_mock, legacy_patchable_time, caplog
 ):
diff --git a/tests/components/mqtt/test_camera.py b/tests/components/mqtt/test_camera.py
index 6869b530668..22f714fdcf7 100644
--- a/tests/components/mqtt/test_camera.py
+++ b/tests/components/mqtt/test_camera.py
@@ -16,6 +16,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -30,6 +31,7 @@ from .test_common import (
     help_test_update_with_json_attrs_not_dict,
 )
 
+from tests.async_mock import patch
 from tests.common import async_fire_mqtt_message
 
 DEFAULT_CONFIG = {
@@ -153,14 +155,25 @@ async def test_discovery_update_camera(hass, mqtt_mock, caplog):
     entry = hass.config_entries.async_entries(mqtt.DOMAIN)[0]
     await async_start(hass, "homeassistant", entry)
 
-    data1 = '{ "name": "Beer",' '  "topic": "test_topic"}'
-    data2 = '{ "name": "Milk",' '  "topic": "test_topic"}'
+    data1 = '{ "name": "Beer", "topic": "test_topic"}'
+    data2 = '{ "name": "Milk", "topic": "test_topic"}'
 
     await help_test_discovery_update(
         hass, mqtt_mock, caplog, camera.DOMAIN, data1, data2
     )
 
 
+async def test_discovery_update_unchanged_camera(hass, mqtt_mock, caplog):
+    """Test update of discovered camera."""
+    data1 = '{ "name": "Beer", "topic": "test_topic"}'
+    with patch(
+        "homeassistant.components.mqtt.camera.MqttCamera.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, camera.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
@@ -168,7 +181,7 @@ async def test_discovery_broken(hass, mqtt_mock, caplog):
     await async_start(hass, "homeassistant", entry)
 
     data1 = '{ "name": "Beer" }'
-    data2 = '{ "name": "Milk",' '  "topic": "test_topic"}'
+    data2 = '{ "name": "Milk", "topic": "test_topic"}'
 
     await help_test_discovery_broken(
         hass, mqtt_mock, caplog, camera.DOMAIN, data1, data2
diff --git a/tests/components/mqtt/test_climate.py b/tests/components/mqtt/test_climate.py
index 6a7bdf0b7e6..d60af211d71 100644
--- a/tests/components/mqtt/test_climate.py
+++ b/tests/components/mqtt/test_climate.py
@@ -34,6 +34,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -48,7 +49,7 @@ from .test_common import (
     help_test_update_with_json_attrs_not_dict,
 )
 
-from tests.async_mock import call
+from tests.async_mock import call, patch
 from tests.common import async_fire_mqtt_message
 from tests.components.climate import common
 
@@ -909,11 +910,22 @@ async def test_discovery_update_climate(hass, mqtt_mock, caplog):
     )
 
 
+async def test_discovery_update_unchanged_climate(hass, mqtt_mock, caplog):
+    """Test update of discovered climate."""
+    data1 = '{ "name": "Beer" }'
+    with patch(
+        "homeassistant.components.mqtt.climate.MqttClimate.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, CLIMATE_DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
-    data1 = '{ "name": "Beer",' '  "power_command_topic": "test_topic#" }'
-    data2 = '{ "name": "Milk", ' '  "power_command_topic": "test_topic" }'
+    data1 = '{ "name": "Beer", "power_command_topic": "test_topic#" }'
+    data2 = '{ "name": "Milk", "power_command_topic": "test_topic" }'
     await help_test_discovery_broken(
         hass, mqtt_mock, caplog, CLIMATE_DOMAIN, data1, data2
     )
diff --git a/tests/components/mqtt/test_common.py b/tests/components/mqtt/test_common.py
index 31566885a37..89bfde22d87 100644
--- a/tests/components/mqtt/test_common.py
+++ b/tests/components/mqtt/test_common.py
@@ -497,6 +497,29 @@ async def help_test_discovery_update(hass, mqtt_mock, caplog, domain, data1, dat
     assert state is None
 
 
+async def help_test_discovery_update_unchanged(
+    hass, mqtt_mock, caplog, domain, data1, discovery_update
+):
+    """Test update of discovered component without changes.
+
+    This is a test helper for the MqttDiscoveryUpdate mixin.
+    """
+    entry = hass.config_entries.async_entries(mqtt.DOMAIN)[0]
+    await async_start(hass, "homeassistant", entry)
+
+    async_fire_mqtt_message(hass, f"homeassistant/{domain}/bla/config", data1)
+    await hass.async_block_till_done()
+
+    state = hass.states.get(f"{domain}.beer")
+    assert state is not None
+    assert state.name == "Beer"
+
+    async_fire_mqtt_message(hass, f"homeassistant/{domain}/bla/config", data1)
+    await hass.async_block_till_done()
+
+    assert not discovery_update.called
+
+
 async def help_test_discovery_broken(hass, mqtt_mock, caplog, domain, data1, data2):
     """Test handling of bad discovery message."""
     entry = hass.config_entries.async_entries(mqtt.DOMAIN)[0]
diff --git a/tests/components/mqtt/test_cover.py b/tests/components/mqtt/test_cover.py
index c3f00badef8..f9036bcfa0f 100644
--- a/tests/components/mqtt/test_cover.py
+++ b/tests/components/mqtt/test_cover.py
@@ -38,6 +38,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -52,6 +53,7 @@ from .test_common import (
     help_test_update_with_json_attrs_not_dict,
 )
 
+from tests.async_mock import patch
 from tests.common import async_fire_mqtt_message
 
 DEFAULT_CONFIG = {
@@ -1862,24 +1864,35 @@ async def test_unique_id(hass, mqtt_mock):
 
 async def test_discovery_removal_cover(hass, mqtt_mock, caplog):
     """Test removal of discovered cover."""
-    data = '{ "name": "test",' '  "command_topic": "test_topic" }'
+    data = '{ "name": "test", "command_topic": "test_topic" }'
     await help_test_discovery_removal(hass, mqtt_mock, caplog, cover.DOMAIN, data)
 
 
 async def test_discovery_update_cover(hass, mqtt_mock, caplog):
     """Test update of discovered cover."""
-    data1 = '{ "name": "Beer",' '  "command_topic": "test_topic" }'
-    data2 = '{ "name": "Milk",' '  "command_topic": "test_topic" }'
+    data1 = '{ "name": "Beer", "command_topic": "test_topic" }'
+    data2 = '{ "name": "Milk", "command_topic": "test_topic" }'
     await help_test_discovery_update(
         hass, mqtt_mock, caplog, cover.DOMAIN, data1, data2
     )
 
 
+async def test_discovery_update_unchanged_cover(hass, mqtt_mock, caplog):
+    """Test update of discovered cover."""
+    data1 = '{ "name": "Beer", "command_topic": "test_topic" }'
+    with patch(
+        "homeassistant.components.mqtt.cover.MqttCover.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, cover.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
-    data1 = '{ "name": "Beer",' '  "command_topic": "test_topic#" }'
-    data2 = '{ "name": "Milk",' '  "command_topic": "test_topic" }'
+    data1 = '{ "name": "Beer", "command_topic": "test_topic#" }'
+    data2 = '{ "name": "Milk", "command_topic": "test_topic" }'
     await help_test_discovery_broken(
         hass, mqtt_mock, caplog, cover.DOMAIN, data1, data2
     )
diff --git a/tests/components/mqtt/test_fan.py b/tests/components/mqtt/test_fan.py
index 6114fe48ff4..e1801c5c15a 100644
--- a/tests/components/mqtt/test_fan.py
+++ b/tests/components/mqtt/test_fan.py
@@ -19,6 +19,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -33,6 +34,7 @@ from .test_common import (
     help_test_update_with_json_attrs_not_dict,
 )
 
+from tests.async_mock import patch
 from tests.common import async_fire_mqtt_message
 from tests.components.fan import common
 
@@ -689,22 +691,33 @@ async def test_unique_id(hass, mqtt_mock):
 
 async def test_discovery_removal_fan(hass, mqtt_mock, caplog):
     """Test removal of discovered fan."""
-    data = '{ "name": "test",' '  "command_topic": "test_topic" }'
+    data = '{ "name": "test", "command_topic": "test_topic" }'
     await help_test_discovery_removal(hass, mqtt_mock, caplog, fan.DOMAIN, data)
 
 
 async def test_discovery_update_fan(hass, mqtt_mock, caplog):
     """Test update of discovered fan."""
-    data1 = '{ "name": "Beer",' '  "command_topic": "test_topic" }'
-    data2 = '{ "name": "Milk",' '  "command_topic": "test_topic" }'
+    data1 = '{ "name": "Beer", "command_topic": "test_topic" }'
+    data2 = '{ "name": "Milk", "command_topic": "test_topic" }'
     await help_test_discovery_update(hass, mqtt_mock, caplog, fan.DOMAIN, data1, data2)
 
 
+async def test_discovery_update_unchanged_fan(hass, mqtt_mock, caplog):
+    """Test update of discovered fan."""
+    data1 = '{ "name": "Beer", "command_topic": "test_topic" }'
+    with patch(
+        "homeassistant.components.mqtt.fan.MqttFan.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, fan.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
     data1 = '{ "name": "Beer" }'
-    data2 = '{ "name": "Milk",' '  "command_topic": "test_topic" }'
+    data2 = '{ "name": "Milk", "command_topic": "test_topic" }'
     await help_test_discovery_broken(hass, mqtt_mock, caplog, fan.DOMAIN, data1, data2)
 
 
diff --git a/tests/components/mqtt/test_legacy_vacuum.py b/tests/components/mqtt/test_legacy_vacuum.py
index 893c1b78f1e..aacea4e345e 100644
--- a/tests/components/mqtt/test_legacy_vacuum.py
+++ b/tests/components/mqtt/test_legacy_vacuum.py
@@ -31,6 +31,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -45,6 +46,7 @@ from .test_common import (
     help_test_update_with_json_attrs_not_dict,
 )
 
+from tests.async_mock import patch
 from tests.common import async_fire_mqtt_message
 from tests.components.vacuum import common
 
@@ -643,6 +645,17 @@ async def test_discovery_update_vacuum(hass, mqtt_mock, caplog):
     )
 
 
+async def test_discovery_update_unchanged_vacuum(hass, mqtt_mock, caplog):
+    """Test update of discovered vacuum."""
+    data1 = '{ "name": "Beer", "command_topic": "test_topic" }'
+    with patch(
+        "homeassistant.components.mqtt.vacuum.schema_legacy.MqttVacuum.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, vacuum.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
diff --git a/tests/components/mqtt/test_light.py b/tests/components/mqtt/test_light.py
index 5fa8fa181e5..75d3e694838 100644
--- a/tests/components/mqtt/test_light.py
+++ b/tests/components/mqtt/test_light.py
@@ -170,6 +170,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -1450,6 +1451,21 @@ async def test_discovery_update_light(hass, mqtt_mock, caplog):
     )
 
 
+async def test_discovery_update_unchanged_light(hass, mqtt_mock, caplog):
+    """Test update of discovered light."""
+    data1 = (
+        '{ "name": "Beer",'
+        '  "state_topic": "test_topic",'
+        '  "command_topic": "test_topic" }'
+    )
+    with patch(
+        "homeassistant.components.mqtt.light.schema_basic.MqttLight.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, light.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
diff --git a/tests/components/mqtt/test_light_json.py b/tests/components/mqtt/test_light_json.py
index 7bb3763654e..54292aeeb7b 100644
--- a/tests/components/mqtt/test_light_json.py
+++ b/tests/components/mqtt/test_light_json.py
@@ -110,6 +110,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -1179,6 +1180,22 @@ async def test_discovery_update_light(hass, mqtt_mock, caplog):
     )
 
 
+async def test_discovery_update_unchanged_light(hass, mqtt_mock, caplog):
+    """Test update of discovered light."""
+    data1 = (
+        '{ "name": "Beer",'
+        '  "schema": "json",'
+        '  "state_topic": "test_topic",'
+        '  "command_topic": "test_topic" }'
+    )
+    with patch(
+        "homeassistant.components.mqtt.light.schema_json.MqttLightJson.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, light.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
diff --git a/tests/components/mqtt/test_light_template.py b/tests/components/mqtt/test_light_template.py
index f0e226d2095..17b3332da40 100644
--- a/tests/components/mqtt/test_light_template.py
+++ b/tests/components/mqtt/test_light_template.py
@@ -47,6 +47,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -923,6 +924,24 @@ async def test_discovery_update_light(hass, mqtt_mock, caplog):
     )
 
 
+async def test_discovery_update_unchanged_light(hass, mqtt_mock, caplog):
+    """Test update of discovered light."""
+    data1 = (
+        '{ "name": "Beer",'
+        '  "schema": "template",'
+        '  "state_topic": "test_topic",'
+        '  "command_topic": "test_topic",'
+        '  "command_on_template": "on",'
+        '  "command_off_template": "off"}'
+    )
+    with patch(
+        "homeassistant.components.mqtt.light.schema_template.MqttLightTemplate.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, light.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
diff --git a/tests/components/mqtt/test_lock.py b/tests/components/mqtt/test_lock.py
index ff130077a95..cd37543d94e 100644
--- a/tests/components/mqtt/test_lock.py
+++ b/tests/components/mqtt/test_lock.py
@@ -20,6 +20,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -34,6 +35,7 @@ from .test_common import (
     help_test_update_with_json_attrs_not_dict,
 )
 
+from tests.async_mock import patch
 from tests.common import async_fire_mqtt_message
 
 DEFAULT_CONFIG = {
@@ -382,6 +384,21 @@ async def test_discovery_update_lock(hass, mqtt_mock, caplog):
     await help_test_discovery_update(hass, mqtt_mock, caplog, LOCK_DOMAIN, data1, data2)
 
 
+async def test_discovery_update_unchanged_lock(hass, mqtt_mock, caplog):
+    """Test update of discovered lock."""
+    data1 = (
+        '{ "name": "Beer",'
+        '  "state_topic": "test_topic",'
+        '  "command_topic": "command_topic" }'
+    )
+    with patch(
+        "homeassistant.components.mqtt.lock.MqttLock.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, LOCK_DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
diff --git a/tests/components/mqtt/test_sensor.py b/tests/components/mqtt/test_sensor.py
index 5ec5fccbe28..0d31b9f33f2 100644
--- a/tests/components/mqtt/test_sensor.py
+++ b/tests/components/mqtt/test_sensor.py
@@ -24,6 +24,7 @@ from .test_common import (
     help_test_discovery_update,
     help_test_discovery_update_attr,
     help_test_discovery_update_availability,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info,
     help_test_entity_debug_info_max_messages,
     help_test_entity_debug_info_message,
@@ -425,24 +426,35 @@ async def test_unique_id(hass, mqtt_mock):
 
 async def test_discovery_removal_sensor(hass, mqtt_mock, caplog):
     """Test removal of discovered sensor."""
-    data = '{ "name": "test",' '  "state_topic": "test_topic" }'
+    data = '{ "name": "test", "state_topic": "test_topic" }'
     await help_test_discovery_removal(hass, mqtt_mock, caplog, sensor.DOMAIN, data)
 
 
 async def test_discovery_update_sensor(hass, mqtt_mock, caplog):
     """Test update of discovered sensor."""
-    data1 = '{ "name": "Beer",' '  "state_topic": "test_topic" }'
-    data2 = '{ "name": "Milk",' '  "state_topic": "test_topic" }'
+    data1 = '{ "name": "Beer", "state_topic": "test_topic" }'
+    data2 = '{ "name": "Milk", "state_topic": "test_topic" }'
     await help_test_discovery_update(
         hass, mqtt_mock, caplog, sensor.DOMAIN, data1, data2
     )
 
 
+async def test_discovery_update_unchanged_sensor(hass, mqtt_mock, caplog):
+    """Test update of discovered sensor."""
+    data1 = '{ "name": "Beer", "state_topic": "test_topic" }'
+    with patch(
+        "homeassistant.components.mqtt.sensor.MqttSensor.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, sensor.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
-    data1 = '{ "name": "Beer",' '  "state_topic": "test_topic#" }'
-    data2 = '{ "name": "Milk",' '  "state_topic": "test_topic" }'
+    data1 = '{ "name": "Beer", "state_topic": "test_topic#" }'
+    data2 = '{ "name": "Milk", "state_topic": "test_topic" }'
     await help_test_discovery_broken(
         hass, mqtt_mock, caplog, sensor.DOMAIN, data1, data2
     )
diff --git a/tests/components/mqtt/test_state_vacuum.py b/tests/components/mqtt/test_state_vacuum.py
index c8ca7d3691b..fe410821395 100644
--- a/tests/components/mqtt/test_state_vacuum.py
+++ b/tests/components/mqtt/test_state_vacuum.py
@@ -41,6 +41,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -55,6 +56,7 @@ from .test_common import (
     help_test_update_with_json_attrs_not_dict,
 )
 
+from tests.async_mock import patch
 from tests.common import async_fire_mqtt_message
 from tests.components.vacuum import common
 
@@ -410,24 +412,35 @@ async def test_unique_id(hass, mqtt_mock):
 
 async def test_discovery_removal_vacuum(hass, mqtt_mock, caplog):
     """Test removal of discovered vacuum."""
-    data = '{ "schema": "state", "name": "test",' '  "command_topic": "test_topic"}'
+    data = '{ "schema": "state", "name": "test", "command_topic": "test_topic"}'
     await help_test_discovery_removal(hass, mqtt_mock, caplog, vacuum.DOMAIN, data)
 
 
 async def test_discovery_update_vacuum(hass, mqtt_mock, caplog):
     """Test update of discovered vacuum."""
-    data1 = '{ "schema": "state", "name": "Beer",' '  "command_topic": "test_topic"}'
-    data2 = '{ "schema": "state", "name": "Milk",' '  "command_topic": "test_topic"}'
+    data1 = '{ "schema": "state", "name": "Beer", "command_topic": "test_topic"}'
+    data2 = '{ "schema": "state", "name": "Milk", "command_topic": "test_topic"}'
     await help_test_discovery_update(
         hass, mqtt_mock, caplog, vacuum.DOMAIN, data1, data2
     )
 
 
+async def test_discovery_update_unchanged_vacuum(hass, mqtt_mock, caplog):
+    """Test update of discovered vacuum."""
+    data1 = '{ "schema": "state", "name": "Beer", "command_topic": "test_topic"}'
+    with patch(
+        "homeassistant.components.mqtt.vacuum.schema_state.MqttStateVacuum.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, vacuum.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""
-    data1 = '{ "schema": "state", "name": "Beer",' '  "command_topic": "test_topic#"}'
-    data2 = '{ "schema": "state", "name": "Milk",' '  "command_topic": "test_topic"}'
+    data1 = '{ "schema": "state", "name": "Beer", "command_topic": "test_topic#"}'
+    data2 = '{ "schema": "state", "name": "Milk", "command_topic": "test_topic"}'
     await help_test_discovery_broken(
         hass, mqtt_mock, caplog, vacuum.DOMAIN, data1, data2
     )
diff --git a/tests/components/mqtt/test_switch.py b/tests/components/mqtt/test_switch.py
index 869a413eb6b..a6edb8d6f14 100644
--- a/tests/components/mqtt/test_switch.py
+++ b/tests/components/mqtt/test_switch.py
@@ -15,6 +15,7 @@ from .test_common import (
     help_test_discovery_removal,
     help_test_discovery_update,
     help_test_discovery_update_attr,
+    help_test_discovery_update_unchanged,
     help_test_entity_debug_info_message,
     help_test_entity_device_info_remove,
     help_test_entity_device_info_update,
@@ -320,6 +321,21 @@ async def test_discovery_update_switch(hass, mqtt_mock, caplog):
     )
 
 
+async def test_discovery_update_unchanged_switch(hass, mqtt_mock, caplog):
+    """Test update of discovered switch."""
+    data1 = (
+        '{ "name": "Beer",'
+        '  "state_topic": "test_topic",'
+        '  "command_topic": "test_topic" }'
+    )
+    with patch(
+        "homeassistant.components.mqtt.switch.MqttSwitch.discovery_update"
+    ) as discovery_update:
+        await help_test_discovery_update_unchanged(
+            hass, mqtt_mock, caplog, switch.DOMAIN, data1, discovery_update
+        )
+
+
 @pytest.mark.no_fail_on_log_exception
 async def test_discovery_broken(hass, mqtt_mock, caplog):
     """Test handling of bad discovery message."""