diff --git a/juju/model.py b/juju/model.py
index a3d4088c..715b8ed5 100644
--- a/juju/model.py
+++ b/juju/model.py
@@ -65,7 +65,7 @@
 from ._sync import SyncCacheLine, ThreadedAsyncRunner
 
 if TYPE_CHECKING:
-    from .client._definitions import ApplicationStatus, FullStatus
+    from .client._definitions import ApplicationStatus, FullStatus, UnitStatus
     from .application import Application
     from .machine import Machine
     from .relation import Relation
@@ -3062,11 +3062,58 @@ async def _check_idle(
         expected_idle_since = now - timedelta(seconds=idle_period)
         full_status = await self.get_status()
 
+        # FIXME check this precedence
+        for app_name in apps:
+            if not full_status.applications.get(app_name):
+                logging.info("Waiting for app %r", app_name)
+                return False
+
+        # priority order is this:
+        #
+        # Machine error (any unit of any app from apps)
+        # Agent error (-"-)
+        # Workload error (-"-)
+        # App error (any app from apps)
+        #
+        # Workload blocked (any unit of any app from apps)
+        # App blocked (any app from apps)
+        units: Dict[str, UnitStatus] = {}
+        for app_name in apps:
+            #assert full_status.applications[app_name]
+            app = full_status.applications[app_name]
+            assert app
+            for unit_name, unit in app.units.items():
+                assert unit
+                units[unit_name] = unit
+
+        for unit_name, unit in units.items():
+            if unit.machine:
+                ...
+
+        for unit_name, unit in units.items():
+            if unit.agent_status.status == "error" and ...:
+                ...
+
+        for unit_name, unit in units.items():
+            if unit.workload_status.status == "errpr" and ...:
+                ...
+
+        # add app check
+
+        for unit_name, unit in units.items():
+            if unit.workload_status.status == "blocked" and ...:
+                ...
+
+        # add app check
+
+
+        # remove this
         for app_name in apps:
             if not (app := full_status.applications.get(app_name)):
                 logging.info("Waiting for app %r", app_name)
                 return False
 
+            # FIXME compound status is not effective
             app_status, app_info = self._compound_status(full_status, app_name)
             if app_status == "error" and raise_on_error:
                 raise JujuAppError(f"App {app_name!r} is in error: {app_info!r}")