My former Ts used to say "it's time to stop" or "we just have a couple of minutes left". I used to watch the clock because I never wanted my session to end. I still don't want them to end, but my current T ususually gives me enough warning so that we can wrap things up. Often my eyes are closed so I don't know how much time we have left but I can usually tell if she doesn't say anything. Often she asks "how can we end so you're all right" or something to that effect. She used to go over the time but she usually has someone after me now so she can't. If I'm her last client she says we can walk out together and we do. She never just says "it's time to go. Good-bye".