The existing walls are various colors in different rooms. They range from light brown, to yellow to pink!
We are using a white primer on our walls.
The consultant at the paint store recommends priming and then painting two coats. The skeptic in me thinks that want us to buy more paint by suggesting two coats.
Realistically, when would I need two coats? If the walls look good after one coat do I need another coat?
You should add another coat if you don't think it looks good enough. If you think it looks good with one coat, don't put on a second.
In more concrete terms, you generally add another coat if the color or finish is not even. That may come with one coat, or it may take two, three, or even more. It depends on the surface, the primer, the paint, any existing finish, technique, thickness of the coat of paint, etc.
Covering up dark colors with light colors generally requires more coats, but a good primer can reduce the number of coats of paint needed. Using a tinted primer generally means fewer coats are needed.
For painting over previously painted surfaces you do NOT need primer. High quality primers do not hide colors very well because they are designed to adhere to a raw surface and typically do not carry many "solids" to cover. In fact the highest build and cost primer we use turns almost clear when it dries.
I also suspect one coat of paint will not give you the results you would like if you go over any darker colors; even with higher quality paint because you will not get even enough coverage to hide the old colors.
That being said, I would recommend simply 2 coats of just about any paint if you are simply trying to recolor; even cheap paint; and no primer. Just know you get what you pay for in paint beyond simply changing the color. On average, high cost paints will adhere better, hold up to abuse more, and generally last longer than cheaper paint.
I am not a contractor, however I do paint often. My first advice is use quality products (always), Kilz 2 is a good primer, and Sherwin Williams is good paint. I know there are many others, but these are what I use. Secondly if you put a good solid coat of paint on your first coat, take a look at how it looks. Don't try and conserve your first coat... painting the wall is your goal so put a solid layer of paint on evenly. Each room may differ, so take a good look at it during different parts of the day- you may not need a second coat if everything looks good and the old paint cannot be traced anywhere.
I just painted a 3000 sqft house so here is my 2 cents. When we got the house, there were dark red, dark green, brown and yellow, we wanted to make it pure flat white. I started with the red wall, it took 4 coats to cover, but I doubt that there might have been some psychological factor since I always thought it's not white enough yet, but 3 coats definitely won't cover evenly. You don't want to recoat when the previous one is not completely dry, wait at least 3-4 hours under ideal conditions, because the result changes after it dries, so you want to wait.
Also, the worst thing you can do is to retouch an area right after you put on the coat since it's drier than the fresh paint, it will become a mess. I use behr primer & sealer, it's about 1/3 of the price of paint and covers the dark colors really really well, although it appears thinner in the can but covers better than paint so it's a much more cost effective approach in my case.
