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.
Over the past year I have had several jobs given to 2 Angie's list recommendations and 1 not from a recommendation. They all have one thing in common, lack of sufficient and correct preparation to save time, labor, and the fact that they put a person in charge that was a cut corners type of worker. The two from Angie's list sent worker/s back to try touch up problems, but once the job is not prepared correctly in the first place any extra work is like putting a band-aid on a dirty wound.
David took so much pride in his work and was really wonderful about communicating with us each step of the way. His crew painted the interior AND exterior of our home in maybe a week or less. I love how they painted our pipes outside of the house to match the colors- I'll attach a picture to show what I mean. Their attention to detail was fantastic! They seriously did not miss a spot and there was zero paint in any place that it wasn't supposed to be!
Beginning with the prep work and ending with last coat of paint or the finishing, an exterior paint job will last anywhere from one to two weeks. After completion, homeowners using low-quality paint will need to repaint every four or five years to keep it well maintained; homeowners using high-quality paint can go longer without a new coat -- usually about seven or eight years, depending on the type of paint and material.