I start the clock as soon as they are in, but when their time is up, it is up. I only go over if they are nearly there or I am enjoying myself (rare) so they wash and get ready in my time. Almost all will take a shower after, but I rarely have anyone taking the P...I have only had to tell someone to 'Go now, I have stuff to do' Once...which is astonishing I think. Mind you since a LOT of my clients are lunch hour or before/after work city types and so many of them are in a rush that most leave early, if not bang on time.