• One room or the whole house? Applying one coat in one room is a reasonable DIY Saturday project (especially if you have help and beer). Multiply the time spent moving furniture, prepping walls and sanding old trim by the number of rooms in the house, and you might want to hire real help. It's the same outside. You can probably tackle one shady garage wall that needs a little scraping and sanding plus a coat of paint, but covering all surfaces of the house is usually best left to a pro.
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.
Did you even read the article? It was specifying UNSCRUPULOUS painters! And, by the way, the photo at the top was not identified at all. How would anyone know whether it was done by a homeowner or not? Also did you ever stop to think that if a consumer has the knowlege to spot a dishonest contractor then by default he also has the knowlege to identify an honest one as well? And, pardon me, but just because you've never seen something has absolutely nothing to do with whether it has actually happened to someone else. Why would any honest business person be so defensive about the publishing of such useful information? If any painters/painting contractors object to a consumer having this kind of information maybe they are the dishonest ones!