diff --git a/bin/i3-companion b/bin/i3-companion
index 542fb84..afcbd43 100755
--- a/bin/i3-companion
+++ b/bin/i3-companion
@@ -144,7 +144,7 @@ def retry(max_retries):
             retries = max_retries
             while True:
                 try:
-                    logger.debug(f"execute {fn} (remaining tries: {retries})")
+                    logger.debug("execute %s (remaining tries: %s)", fn, retries)
                     return await fn(*args, **kwargs)
                 except Exception as e:
                     if retries > 0:
@@ -177,7 +177,7 @@ def debounce(sleep, *, unless=None):
                     await asyncio.wait_for(
                         workers[fn].urgent.wait(), timeout=sleep
                     )
-                    logger.debug(f"urgent work received for {fn}")
+                    logger.debug("urgent work received for %s", fn)
                 except asyncio.TimeoutError:
                     pass
                 args, kwargs = workers[fn].queue
@@ -185,11 +185,11 @@ def debounce(sleep, *, unless=None):
                 workers[fn].urgent.clear()
 
                 # Execute the work
-                logger.debug(f"execute work for {fn}")
+                logger.debug("execute work for %s", fn)
                 try:
                     await fn(*args, **kwargs)
                 except Exception as e:
-                    logger.debug(f"while running {fn}, worker got %s", e)
+                    logger.debug("while running %s, worker got %s", fn, e)
                     workers[fn] = None
                     raise
 
@@ -198,21 +198,21 @@ def debounce(sleep, *, unless=None):
                     break
 
             # No more work
-            logger.debug(f"no more work for {fn}")
+            logger.debug("no more work for %s", fn)
             workers[fn] = None
 
         @functools.wraps(fn)
         async def wrapper(*args, **kwargs):
             if workers[fn] is None:
-                logger.debug(f"create new worker for {fn}")
+                logger.debug("create new worker for %s", fn)
                 workers[fn] = types.SimpleNamespace()
                 workers[fn].task = asyncio.create_task(worker())
                 workers[fn].urgent = asyncio.Event()
                 workers[fn].queue = (args, kwargs)
             else:
-                logger.debug(f"enqueue new work for {fn}")
+                logger.debug("enqueue new work for %s", fn)
             if unless is not None and unless(*args, **kwargs):
-                logger.debug(f"wake up now for {fn}")
+                logger.debug("wake up now for %s", fn)
                 workers[fn].urgent.set()
             return await workers[fn].task
 
@@ -282,7 +282,7 @@ async def workspace_rename(i3, event):
                 continue
             for k, v in application_icons.items():
                 if re.match(rf"^{k}\b", name, re.IGNORECASE):
-                    logger.debug(f"in {attr}, found '{name}', matching {k}")
+                    logger.debug("in %s, found '%s', matching %s", attr, name, k)
                     return v
         return application_icons_nomatch
 
@@ -298,7 +298,7 @@ async def workspace_rename(i3, event):
             icons -= application_icons_alone
         new_name = f"{workspace.num}:{'|'.join(icons)}".rstrip(":")
         if workspace.name != new_name:
-            logger.debug(f"rename workspace {workspace.num}")
+            logger.debug("rename workspace %s", workspace.num)
             command = f'rename workspace "{workspace.name}" to "{new_name}"'
             commands.append(command)
     await i3.command(";".join(commands))
@@ -356,7 +356,7 @@ async def worksplace_exclusive(i3, event):
 
     # Can the new window just intrude?
     if can_intrude(w):
-        logger.debug(f"window {w.name} can intrude")
+        logger.debug("window %s can intrude", w.name)
         return
 
     # Get the workspace. From an event, w.workspace() is None, so
@@ -377,7 +377,7 @@ async def worksplace_exclusive(i3, event):
     }
     exclusives = ids.intersection(exclusive_apps)
     if not exclusives:
-        logger.debug("no exclusive app, {w.name} can go there")
+        logger.debug("no exclusive app, %s can go there", w.name)
         return
 
     # Create a new workspace and move the window here
@@ -426,7 +426,7 @@ async def quake_console(i3, event):
         "scratchpad show,"
         f"move absolute position {posx}px {posy}px"
     )
-    logger.debug(f"QuakeConsole: {command}")
+    logger.debug("QuakeConsole: %s", command)
     await i3.command(command)
 
 
@@ -761,7 +761,7 @@ async def dunst_status_check(i3, event):
 async def network_manager_notifications(i3, event, path, state, reason):
     """Display notifications related to Network Manager state."""
     ofnm = "org.freedesktop.NetworkManager"
-    logger.debug(f"from {path} state: {state}, reason: {reason}")
+    logger.debug("from %s state: %s, reason: %s", path, state, reason)
     if state not in {NM_ACTIVE_CONNECTION_STATE_ACTIVATED}:
         # Deactivated state does not contain enough information,
         # unless we maintain state.
@@ -899,7 +899,12 @@ async def main(options):
     for fn, events in on.functions.items():
         for event in events:
             if isinstance(event, I3Event):
-                i3.on(event, fn)
+                def wrapping(fn, event):
+                    async def wrapped(i3, event):
+                        logger.debug("received i3 event %s for %s", event, fn)
+                        return await fn(i3, event)
+                    return wrapped
+                i3.on(event, wrapping(fn, event))
 
     # React to some bindings
     async def binding_event(i3, event):
@@ -918,6 +923,7 @@ async def main(options):
         for fn, events in on.functions.items():
             for e in events:
                 if isinstance(e, CommandEvent) and e.name == kind:
+                    logger.debug("received command event %s for %s", event, fn)
                     await fn(i3, cmd)
 
     i3.on(I3Event.BINDING, binding_event)
@@ -937,7 +943,10 @@ async def main(options):
                     )
                     async def wrapped(path, args):
                         if event.onlyif is not None and not event.onlyif(args):
+                            logger.debug("received DBus event for %s but not interested",
+                                         fn)
                             return
+                        logger.debug("received DBus event %s for %s", event, fn)
                         return await fn(i3, event, path, *args)
 
                     return wrapped