As the homeowner, I've done all of our interior and most of our painting. Whenever you paint, preparation is truly key. Anyone can slap on a coat of paint and call it done. If you want something that looks good and lasts, take the time to clean the walls (also if there is a smoker in the house, nicotine sticks to paint), fill any holes, and take care of any imperfections in the surface. Also, tape off ceilings, door and window frames, and any other place you don't want paint to land. Depending on the size of the room and the number of doors and windows, it might take you 2-3 times the amount of time to prep as to paint. I've never had a contractor paint in my home, but if I did, the first question I'd ask is for a detailed list of how much preparation they would do. If it wouldn't be at least as thorough as mine, I wouldn't hire them. Also, ask about priming before painting, particularly if you're going to cover a darker color with a lighter one. There are now all in one primer/finish paints. If this is not going to be used, ask to have the primer tinted as close to the finish color as you can get.
Basic labor to paint home with favorable site conditions. Prep up to 3 hr per 100 SF - clean, scrape, sand and patch up to 4 defects per 100 SF. Caulk gaps and spot prime. Roll / brush 2 coats of paint over lightly textured ceiling/walls. Paint up to 2 doors and door trim per room. Includes planning, equipment and material acquisition, area preparation and protection, setup and cleanup. 129 square feet $93.64 $126.68
Most pros don't bother cleaning brushes and rollers if they are going to use them the next day on the same job. "Latex paint dries slowly in cold temperatures," says Maceyunas. For two-day jobs, he wraps the rollers and brushes in plastic grocery bags and sticks them in the refrigerator. "Just allow the roller to return to room temperature before reusing it," he says. Roller covers are almost impossible to clean thoroughly. Most pros buy new covers for each job.