I have a very large one, but it was created years ago, when I had more time on my hands. Since that time, the policies and precedures have changed a great deal. The reporting structure is also quite different.
As a result, the manual is very much out-of-date and not very useful anymore. I need to block off some time to go through it and update all the procedures. If something were to happen to me, my two bosses would look through the manual, but they'd have to start from scratch with a new coordinator. That isn't a fair predicament in which to leave the company at all.
Movinonup 
