nonrefundable deposit on long commission

nonrefundable deposit on commission used to secure materials and schedule time.  Balance on agreed upon price of commission plus taxes is due on final approval.  If painting is not approved, deposit will be retained, artist will keep painting and sell from her studio and client will not be required to pay balance on commission.  Schedule:  3-4 weeks for painting.  Review of completed painting.  If approved I will then varnish painting and it will be ready for pickup in one week after varnishing.  Framing can be explored while painting is being worked on.