My T doesn't do anything in particular. I'm usually keeping an eye on the time, so I tend to start thinking of wrapping things up on my own. It generally seems to happen pretty naturally, though. AT has a specific way of wrapping things up - she does feedback at the end of every session, so she checks the clock and does the wrap up. Sometimes it works out in a smooth way, but other times it's like, "oh, we're out of time - I need to do feedback." Last week it caused our session to end awkwardly because we were in the middle of a particular topic when she noticed the time.