Do you need to paint your house, but also find yourself thinking of walking out of your office for good and picking up a paint gun instead? Does the thought of simple work with immediate results that you can see everyday sound much better than the frustrating mess of dealing with the people in your "white collar" job? Want to be a craftsman? Well guess what? It's not so simple as you might hope... Great book that will give you insight into the world of painting for a living and the folks who do. The authors website is also full of information on how to do the job right the first time. Much appreciated.
If the point of hiring a well established, experienced, reputable painting contractor is to secure the professionalism and trust suggested to be inherent with that choice, then I would EXPECT that professionalism and experience to include the ability to make the proper and correct calculations for labor and materials for a fixed price quote, and there should be NO reason for the contractor to put the cost burden of their miscalculation on the consumer.
Ask companies to include all details in writing. Although that sounds simple enough, too many contractors submit offers such as "paint house for $5,000." A friendly contractor may offer a reassuring handshake and promise that the crew will take care of all the details — starting on time, working every day, cleaning up, etc. That's great, but why not include each point in the proposal? If it's a challenge to get a written description of labor, materials and other details, things will probably get worse when the work starts.