I think the deposit should be non refundable. It should cover the cost of the materials but not necessarily all your time. As long as the person realizes that by only paying half, the quilt is not theirs. Even halfway finished. If you are thinking of adding a changing your mind fee in addition, I don't think so. Once the finished quilt is presented, if they don't like it, they don't pay the other half. But the quilt is yours.