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.

Stacee, I agree with you completely, from adding water to latex paint to taking whites from job to job. This article makes all painters look like scam artists. You get what you pay for people! There is no denying that there are scammers out there but in my experience, most painters are under paid any ways so if you want a good paint job, you are going to pay for it. If you just want a new color on your walls real quick, and that is what you pay for then that's what you pay for people. Most painters get the crap end of the stick and are left with making an entire house look good when it took a lot more than a painter to build the house in the first place. Good painters do not get enough credit. They are not all scammers who are cutting corners!
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.
There are permanent features of the home that have their own colors which cannot be changed when painting the exterior of the home but can have a dramatic satisfaction level that is experienced when the painting is completed.  Roofing shingles, paving blocks, concrete surfaces, stones and other such features are prime examples of the colors that should be considered when selecting your exterior color scheme for the home.  Homeowners can work off of these colors to make a home that looks uniform and luxurious when the exterior painting is complete.

Paint Contractor Co