You never know when a key person will quit, or do something that will require immediate dismissal. You don't need to have people already interviewed, but a good idea on what the candidate pool is, if it will require bringing in new blood from the outside or promote from within. Dumping someone at the level of senior VP (close corp equivalent to a OC) with no prior thought of how that seat will be filled, while sometimes necessary, is also a mark of less effective management from the top.