My T is chronically late, sometimes it annoys me, but mostly I learn to expect it.. So, I show up about 7mins before when my appointment is scheduled to start and I expect to spend about 15mins waiting, maybe a little more. It's not that big of a deal to me, because T always gives me more than enough time in session. However, if your T is starting late all the time and not tacking it on the end of the appointment, then you should bring it up. Those are the kinds of things you should address with your t. Good luck!