Get probably 3-6 estimates in writing, if you get more than that maybe you are out of control. Liability Insurance and Workers Compensation Insurance is good to check on before you hire anyone, don’t just ask confirm it.  Don’t pay any money up front…any. Inspect the job at the end, all of it, with your glasses on. If the estimator or crews are late it is not a good sign. If the painters are older, old enough to need reading glasses, do they have them. If you come across as a picky psycho when you get your estimates the estimator will pick up on this and not have anything to do with you. Contractors know that some customers are not worth dealing with. Paint jobs are not perfect ever, puppies kittens and little kids are. If you are realistic about the whole process maybe you will be happy.