This was too easy. After applying one coat to the walls in this room, I remained undecided for a day whether a second coat of paint was really necessary. I'm old enough to remember the adage, "the more paint, the better". Which is why part of me was demanding that second coat, in spite of the certain advances in paint technology.
Well, I'm glad I paused to think and ask the question. Because with just a quick search online, I read that, "Now, more than ever, one coat coverage is possible." Basically, over the last 10 years of so, advances in paint technology have made one coat of paint a perfectly acceptable option.
The page above was more than enough to settle the question in my mind. However, in course of writing this, while looking up the above adage, I came across even more proof. According to another source, over-application of coats could even be "dangerous". The reason gets a little too technical for the purposes of this blog, but you can read more about it here.