If you are an manager, you have to know or realizes that your management has got successful or failed.
But how would you know that? When does it end?
You can decide the time to review the result of your management by yourself.
You would realize it fails when you have 1 on 1 with your subordinate.
The staffs you manage might look less couraged.
In my conclusion, we have to decide the evaluation date first.
And if possible, you get some feedback from your subordinate directly or indirectly.
You can get feedback from your boss or CEO, etc.
I would like a silver bullet on management, though.