This is pretty similar to what I have been wandering. I was told a male can only produce x amount of sperm plugs in a certain amount of time (but nothing that can be verified). I hope some people with more exp chime in on this thread.
Do you mean for months, or days? The general rule of thumb is 3 days in 3 days out. As in you put the male in with the female for three days, then take him out and let him "rest" for three days in his own tub.