Second: all the tricks of the trade in regard to "cheating" customers is for hustlers and cheaters and NOT established businesses. At the end of the project the job should come out looking professionally painted as specified in the contract. A selected color that takes multiple coats that was not calculated by the contractor should cost more money. It's not the fault of the painter.
Repaint — exteriors especially — before visible signs of wear appear, Bancroft says. Don’t wait until you see peeling or flaking paint. “If I have to spend 40 hours preparing the surface before we can paint, that time is going to result in a lot of extra costs. But if I can spend 10 hours preparing the surfaces to be painted, you’re going to save money,” Freeman says.
If you are going to hire a contractor (professional painter) give a room by room punch list of the fixing of holes small or big, have it identified for the painter to tell you if you need a drywall finisher or if he does this type of work good. Wall repairs can be 3-5 steps to do repairs ( one per day for good drying of patching material and a good sanding) this is what gives you a good paint job only using high quality paint.
Back to the article. You can add water to all latex based paints / thinner to oil based paint. The tinting base has absolutely nothing to do with it. Say you are working outside and throughout the day you have to add a little water to keep the same consistency. If somebody really tried to add 20% to 50% water they no longer would be painting they'd be performing a whitewash or pickle finish.
If you paint over dirty, oily surfaces, the paint will easily chip or peel off. So before painting, clean grimy areas with a deglosser or heavy-duty cleaner intended for prepaint cleaning. They work well to clean painted, varnished or enameled surfaces to improve the adhesion of the new paint. They’re ideal for cleaning greasy or oily areas like kitchen and bathroom walls and removing hand marks around light switches and doorknobs.
Never, never hire "Hanks painting" , he is a scam. He charged me 1800 for an 800 sqft house, with the agreement of painting the gutters. He not only didn't paint the gutters, the paint of the walls and front door is pealing off. He did not sand the door and the wall color is washing off. His people don't know the work and he much less than them since he painted the door.