When a client hires me usually is for a whole project preproduction. It can be the startup for a new game or the research stage for a new feature of a live game. I help them during the whole process of finding the right formula. I work per day, every day is one slot. Every client can get from 1 to 3 slots per week.
Happens that during my service I realize that my help is not needed. It may happen for a lot of reasons. Sometimes I see that the team is on the right track and I am slowing things down. Other times I see that the client that hired me didn’t want my help with game design, so that I am useless.
In any case, my business is not like a therapist. When I realize that I am not needed anymore, I let go the client. I speak with them and explain any reason. It was a pleasure to be there, please leave your testimonial. You will not lose your money, I will not lose my time. Everybody wins.
(and very few of them leave the actual testimonial)