The article and comments were great information to have before deciding how to go about getting a painting job done. I think the important point is that there are several key choices (who to do the work; color, sheen, quality, of paint; how many coats; amount of prep/repairs to be done and by whom, how long the job will take, provisions for changes, how detailed the contract needs to be; advanced deposit/progress payments/final payment; final inspection, etc.) that need to be made and it requires advanced research and planning in order to become well enough informed to make the right choices. Then it requires spending sufficient time to check materials and inspect the quality of the work while it is on-going, raher than waiting to do it all at the end. President Reagan's philosophy of "Trust, but verify." applies.
More recently, professional painters are responsible for all preparation prior to painting. All scraping, sanding, wallpaper removal, caulking, drywall or wood repair, patching, stain removal, filling nail holes or any defects with plaster or putty, cleaning, taping, preparation and priming are considered to be done by the professional contracted painter.
To win work, contractors generally have to bid against other suppliers. To make an accurate bid, they estimate the time and materials required to complete the job. They measure the area to be painted and discuss the type of finish the customer requires. They assess the quality of the surfaces to work out how much remedial work they must carry out before painting. They might have to remove old paint or wall coverings, or repair cracks and other damage. They also calculate the cost of any essential equipment, such as scaffolding for exterior walls.