I book an hour between calls. There is plenty of time to shower before and after. If I shower with you, its included in the time because the fun starts in the shower.

However I'm really not concerned with strict time. If time goes over by 5 or 10 minutes, what does it matter? Being an independent, I have the luxury of choice. When I worked at parlors, time started once you were in the room, and quite often, you had another call right after. I prefer to not work like that.