When hiring a contractor it is always best to hire one who is personally referred to you by someone you trust. Hiring through ads or phone book is hit and miss. Check with your local paints stores, they know the good guys from the bottom feeders. Go to the stores that sell the high quality paints like Benjamin Moore(nonpareil), Pittsburg, Sherwin Williams or Glidden. Don't go the the big box stores for referrals, the people there don't know squat!
In Mark Twain's classic "The Adventures of Tom Sawyer," Tom tricks his friends into painting his aunt's fence. You probably won't get that lucky, but there are good reasons many homeowners keep their painting in-house. No building codes apply to interior decoration; if you do something dumb, you don't risk life and property as you would if you were, say, tackling a rewiring job; and because labor typically accounts for 80 to 85 percent of the price of a paint job, you'll save a ton by doing the work yourself.
These are some fantastic questions to ask and I particularly like the one that is concerned about safety for the painters. After all, if you have a large home and you’re hiring them to paint the exterior of that home then they’ll likely be on scaffolding. Because of that, you need to make sure that the contractor not only provides appropriate safety training, but has the correct liability insurance as well.