diff --git a/server/reflector/services/ics_sync.py b/server/reflector/services/ics_sync.py
index 1d49d24a..56f83495 100644
--- a/server/reflector/services/ics_sync.py
+++ b/server/reflector/services/ics_sync.py
@@ -356,6 +356,44 @@ class ICSSyncService:
         time_since_sync = datetime.now(timezone.utc) - room.ics_last_sync
         return time_since_sync.total_seconds() >= room.ics_fetch_interval
 
+    def _event_data_changed(self, existing: CalendarEvent, new_data: EventData) -> bool:
+        """Check if event data has changed by comparing relevant fields.
+
+        IMPORTANT: When adding fields to CalendarEvent/EventData, update this method
+        and the _COMPARED_FIELDS set below for runtime validation.
+        """
+        # Fields that come from ICS and should trigger updates when changed
+        _COMPARED_FIELDS = {
+            "title",
+            "description",
+            "start_time",
+            "end_time",
+            "location",
+            "attendees",
+            "ics_raw_data",
+        }
+
+        # Runtime exhaustiveness check: ensure we're comparing all EventData fields
+        event_data_fields = set(EventData.__annotations__.keys()) - {"ics_uid"}
+        if event_data_fields != _COMPARED_FIELDS:
+            missing = event_data_fields - _COMPARED_FIELDS
+            extra = _COMPARED_FIELDS - event_data_fields
+            raise RuntimeError(
+                f"_event_data_changed() field mismatch: "
+                f"missing={missing}, extra={extra}. "
+                f"Update the comparison logic when adding/removing fields."
+            )
+
+        return (
+            existing.title != new_data["title"]
+            or existing.description != new_data["description"]
+            or existing.start_time != new_data["start_time"]
+            or existing.end_time != new_data["end_time"]
+            or existing.location != new_data["location"]
+            or existing.attendees != new_data["attendees"]
+            or existing.ics_raw_data != new_data["ics_raw_data"]
+        )
+
     async def _sync_events_to_database(
         self, room_id: str, events: list[EventData]
     ) -> SyncStats:
@@ -371,11 +409,14 @@ class ICSSyncService:
             )
 
             if existing:
-                updated += 1
+                # Only count as updated if data actually changed
+                if self._event_data_changed(existing, event_data):
+                    updated += 1
+                    await calendar_events_controller.upsert(calendar_event)
             else:
                 created += 1
+                await calendar_events_controller.upsert(calendar_event)
 
-            await calendar_events_controller.upsert(calendar_event)
             current_ics_uids.append(event_data["ics_uid"])
 
         # Soft delete events that are no longer in calendar
diff --git a/server/tests/test_ics_sync.py b/server/tests/test_ics_sync.py
index 6ead3868..cac10848 100644
--- a/server/tests/test_ics_sync.py
+++ b/server/tests/test_ics_sync.py
@@ -291,3 +291,43 @@ async def test_ics_sync_service_error_handling():
         result = await sync_service.sync_room_calendar(room)
         assert result["status"] == "error"
         assert "Network error" in result["error"]
+
+
+@pytest.mark.asyncio
+async def test_event_data_changed_exhaustiveness():
+    """Test that _event_data_changed compares all EventData fields (except ics_uid).
+
+    This test ensures programmers don't forget to update the comparison logic
+    when adding new fields to EventData/CalendarEvent.
+    """
+    from reflector.services.ics_sync import EventData
+
+    sync_service = ICSSyncService()
+
+    from reflector.db.calendar_events import CalendarEvent
+
+    now = datetime.now(timezone.utc)
+    event_data: EventData = {
+        "ics_uid": "test-123",
+        "title": "Test",
+        "description": "Desc",
+        "location": "Loc",
+        "start_time": now,
+        "end_time": now + timedelta(hours=1),
+        "attendees": [],
+        "ics_raw_data": "raw",
+    }
+
+    existing = CalendarEvent(
+        room_id="room1",
+        **event_data,
+    )
+
+    # Will raise RuntimeError if fields are missing from comparison
+    result = sync_service._event_data_changed(existing, event_data)
+    assert result is False
+
+    modified_data = event_data.copy()
+    modified_data["title"] = "Changed Title"
+    result = sync_service._event_data_changed(existing, modified_data)
+    assert result is True