I guess I usually just pick up on her body language...her tone changes a bit too when we're closer to the end of the session. Sometimes she'll say we only have a few minutes left, but usually I know anyways just based on non-verbal cues, and at the end or near the end she will usually close the book she takes notes in. It's never awkward; although with my past T, she was a stickler for time so she would give me a five minute warning, a one minute warning, and then cut me off, and that was unpleasant. It didn't feel natural that way. This T is much better about that stuff.