Constant firing can also negatively affect your personal reputation. As a manager your job is to get people to succeed. Firing someone means that ultimately you failed in that. Sometimes this is unavoidable; there are times when people just aren't redeemable. Sometimes it's not. Good managers know the difference, but you have to remember that every time you let someone go for cause, that person probably didn't see it that way. That person has friends who work other places and all of them have a long memory. If word gets out that you quickly remove people who you can't seem to handle, people will want to stop working for you.