As a listing agent, I find that one of the most common ways to "spruce up" a home to prepare it for sale is to paint.  While many people take on this task themselves, painting can be more difficult than you may think.  For those of us with limited time, patience, or skill, hiring a painting contractor may be the answer; before you hire a painting contractor, there are some things you should take into consideration:

• How long has the contractor been in business?  Be sure to hire someone who has been operating for at least 2-3 three years.
• Are employees experienced painters? Make sure the company hires skilled workers. Ask what training or qualifications they have.  
• Does the contractor have the necessary insurance? A reputable, licensed painting contractor will have coverage that protects him, his workers, and you. 
• What kind of preparation work does the painting contractor do? A cheaper job will normally skip much of the prep work to cut corners; a good contractor will take the time to do everything the way it should be done. The workmanship will show in the end, good or bad.
• Can they provide a list of references? CALL THEM!
• Can the painting contractor make recommendations on what materials will work best for your project? A professional keeps up-to-date on the latest products and techniques, makes suggestions for colors and finishes, and is knowledgeable about the latest trends. 
• GET A WRITTEN CONTRACT!  A professional provides customers with written contracts and specifications, including price, time frame, etc. 

Regardless of the project for which you hire a contractor, painting or otherwise, make sure to hire someone with skill, experience, insurance, awareness of safety issues and good workers; that will not likely be the guy with the lowest bid. It doesn't need to be the highest bid either. Just be sure not to hire on price alone.   If the price seems too good to be true, however, it probably is.