Not really. A lady can get labeled a clock watcher by a pissed fucktard who overstayed his welcome. I know several that quit doing 30 minute sessions because the fucktards were staying 60-90 minutes. Both share responsibility, and the fucktard needs to leave and/or pay for time spent. How about those that pay for one hour and stay for four taking advantage of a new lady? I bet most here would congratulate the fucktard.
I go by how good of a time we are actually having. If we are having a good time and are connecting well, then going over a few minutes is not going to matter to me since I`m enjoying myself I see what your asking though, How do you know that your hour is up? I guess, If you have been in it long enough then you kind of just know...
I HATE to be told to leave, so I'm often the one to bug out. When I have a decent erection it takes a talented BJ provider about 2 minutes to finish so I set the buzzer to go off about 10 minutes before my paid time expires and when I hear it, I become more goal directed.