I am getting ready to paint my 3/2 house. My walls are pretty dirty due to living here for four years and having three kids, anyway I need advice on how to paint my walls to get the most coverage. I have been told that paint and primer in one is crap so what should I do? Which brands do you prefer? Also, what type of brushes and roller would I need, I am only painting walls and they have the knockdown texture. Thanks in advance for any good advice!