Paint advice needed

Another question Paint Pros, is it standard practice in the industry to get something in writing as far as work to be done sort of a punch list I guess. I am paying $2,000 upfront and we'll be paying the rest of the job continues. So I feel pretty good about that but I just want to be on the same page as my guy. But don't want to be viewed as an ***. I guess a written estimate is the way to go?