As soon as you decide someone is no longer right for a position, the sooner you move, the better.
And everyone is now thinking I'm trying to make an argument for RG getting rid of MM this year.
Nope: I'm making a criticism of MM. He's too slow to off load assistants who really aren't working out. It never works out well to keep someone in place, even for a single extra season, if they can't get the job done.
"Continuity," limiting change, not creating an even bigger transition, are all lame excuses for not moving on as soon as you know it's no longer the right fit.
I hate to point out anything ND as a good model, but Kelly gets this point.