My wife and I went through our breaker box today, identifying what each one did. We've never done it in the 7+ years we've owned the place.
Two of the breakers, a 20A 110 and a 20A 220, don't seem to have any purpose at all. Weird. Clearly, the wires go somewhere, but where? The only thing we can think to do, short of getting a specialty tool to trace the wires, is to leave them turned off and wait to discover just what doesn't work any more.
Also, I still haven't found why the outlet I blew with the deep fryer still doesn't work. Curiouser and curiouser.