My T has never mentioned any 'rules' about leaving (or anything else?!) I've been seeing her a few months now, and she has always ended the session by asking "would you like to meet next week?" The choice is always mine (of course I always say yes!) No one can force you to pay X amount per hour for another 4 weeks if it's not working for you, surely? Would you go to a hairdressers, be unsatisfied with your style, but turn up and pay for another 4 appointments?