I'm an architect and my firm routinely specifies interior finishes for projects so I thought I'd contribute a professional's perspective on the issue of how many coats of paint are deemed "acceptable". The fact of the matter is the average consumer usually isn't a paint expert and can't be expected to know about all the factors that impact coverage. That knowledge is considered "means and methods" and in a court of law, the responsibility lies with the painter or general contractor, not the consumer. What the consumer should be concerned about is the final result-does it look good and is it what you expected? The simplest way to communicate this to your painter is to stipule in your written agreement that the number of coats will be "as required to cover". That way all the guess work about what kind of primer, how many coats, how color affects the scope of work, etc., is removed from the consumer's responsibility and resides where it belongs-with the professional. In the contract that's why retention is always a good idea-typically 10% is withheld from payment until the job is completed to the satisfaction of the customer. Of course in return you as the customer have to be reasonable about what constitutes a completed job. Just my $.02.
As an owners rep and former estimator for a gc i do expect to pay a reasonable deposit say 10 percent and then weekly progress payments. I am asking the painter to book his time and to do the work on my schedule. Most painting companies are not huge operations they will pay their staff weekly. For most repaints i ask for one tinted primer coat and one finish coat for 100 percent coverage. New work gets one tinted primer and two finish coats for 100 percent coverage. The cost of the paint is not really that different for colors or finish. Brands like european fine paint and C2 are more expensive than Ben Moore and sometimes more difficult to roll based on their consistency. Some home depot brands are as expensive as the Ben Moore and of equal quality others aren't. Red paints are notorious for number of coats required and special priming requirements.
2.                The geographic  situation is very important too. Gaucin is one of the most singular villages in the Ronda mountain area. The Town is like a balcony looking at the Strait of Gibraltar and Africa. Its privileged situation gives to Gaucin a amazing weather in addition to the views. The Villa is configurated by narrows  streets and white Walls. Our idea is to play with white faces and shadows to be integrated with the surroundings
Some contractors work on time and material others on a firm contract. I would never hire the former and am leary of the latter. A contractor may low-ball a bid to get the job planning to make a killing on change orders. If you say good morning to them, they charge you extra for that. If the contract is not very, very specific and extensively fleshed out or if they display their change order schedule prominently on top, show them the door.

House Painter