I do not mean to come off with an edge, however, this is an article for people hiring low bid, uninsured, one man band painters out to "hustle" a buck. Hire reputable, established companies or hire someone you know or have a strong referral from. If you are arguing over watered down paint, ticky, tacky deposits, buying your own supplies, you have hired the wrong guy.
In some cases, professional painters may include additional charges for specialized equipment that homeowners can't purchase on their own. Because professionals have licenses and access to such equipment, it's simpler to let them get those themselves. But providing some of the smaller equipment and extras directly really can help to cut down on the total cost of your project.
The Lead Renovation, Repair and Painting (RRP) Rule establishes requirements for firms and individuals performing renovations, and affects contractors, property managers, and others who disturb painted surfaces. It applies to work in houses, apartments, and child-occupied facilities (such as schools and day-care centers) built before 1978. It includes pre-renovation education requirements as well as training, firm certification, and work practice requirements.