Not only careful communication is essential, but we would greatly recommend, when you pick out your type and brand of paint that you go and pay for it, with the contractor's discount, which is given by Sherwin-Williams and most paint companies. Then you will know how much paint you purchased and the coverage. If it is possible, inspect the work of the painter daily.
Consider purchasing supplies personally to save money. Ask the painter for a bid that separates labor and materials. Then explain that you'll purchase the materials and ask for a list of exactly what will be needed to complete the job. Caulking, for example, is an extra supply commonly used to fill any cracks or damaged areas in your walls -- and one that might be overlooked in an incomplete list.
Skip the do-overs and pick the perfect paint color the first time around. No matter what space, shade, or aesthetic you're looking for, we've got ideas. And then we've got some more ideas. We compiled all our best paint color advice in one place to make it even easier. By the time you're done with this story, you'll have your paint woes all solved.