You need to have your deliverables stated clearly in writing. If they are vague, try to make them not vague. Or along the lines of, 1/3rd of UX project by end o

You need to have your deliverables stated clearly in writing. If they are vague, try to make them not vague. Or along the lines of, 1/3rd of UX project by end of week 1, 2/3rds by week 2, etc. Otherwise, he'll hold back his retention claiming you never completed the work and you will be in no position to claim otherwise.