Second coats on similar colors are almost never recogicnized as being needed until the coat is applied and has dried. ONLY THEN WILL YOU SEE WHETHER IT NEEDS A SECOND COAT or not. Yes, painters can use a cheaper paint then what you paid for. That is solved by getting your own which, I would charge extra for because I will always have to go get more, or add second coat because home owner tried to skimp on paint, or they got the wrong color etc...
Painting contractors work in the property maintenance sector. Depending on their skills and resources, they might specialize in painting different types of buildings, including houses and apartments, or commercial properties, such as offices, factories or retail outlets. Some contractors work directly for property owners; others find work through real estate firms, rental agents and property maintenance companies.
I have a Home Improvement/Painting business, and Angie's List always advertises that that everyone is out to get them. Of course there are people who try to take advantage of homeowners My reputation and repeat business is based on word of mouth. Shoddy work is always a way to get put out of business quick. As far as strictly painting, preparation is a big factor in getting a quality paint job. If you don't prepare the surfaces you are painting you are spinning your wheels, and wasting money, no matter what paint you use. Getting a deposit from a customer is beneficial, but not always necessary. Sometimes it is a godsend, when you get stuck by the customer, which has happened to me more than once
As you walk through your lighted rooms (preferably day light) see if the new coat has light spots showing the precious paint. This is call "bleeding through". This means that there's only one coat of paint or the paint was diluted or the trasition of colors were from light to dark (or the other way around) and primer was not use or the painter is inexperienced.
Not only careful communication is essential, but we would greatly recommend, when you pick out your type and brand of paint that you go and pay for it, with the contractor's discount, which is given by Sherwin-Williams and most paint companies. Then you will know how much paint you purchased and the coverage. If it is possible, inspect the work of the painter daily.
Climate is another factor to consider. Sunlight, wind, rain and salty weather can all wear out exterior paint. Oil-based paint is durable against wind, rain and temperature changes, but sunlight tends to degrade it. Alkyd paint chalks and sheds very thin layers when it begins to wear. Latex paint is the more durable option for very sun-drenched and relatively dry climate areas. Latex paint with high vinyl content should be avoided, however. Acrylic resin is by far the more durable binder for outdoor latex paint.
Consider purchasing supplies personally to save money. Ask the painter for a bid that separates labor and materials. Then explain that you'll purchase the materials and ask for a list of exactly what will be needed to complete the job. Caulking, for example, is an extra supply commonly used to fill any cracks or damaged areas in your walls -- and one that might be overlooked in an incomplete list.

This was very helpful. I wonder if i would really follow through and check to see if my painter was cheating me. I used a painter I found on Angie's List. This was 5 years ago. He did a great job. I know he did patching only for about a day and a half. We decided on the kind of paint before he started. that is what he used. I don't know if I could stay on top of him and watch him open every can of paint.

Painting Contractor Co