To save time and get a more uniform result when painting with a roller pour your paint in a five gallon bucket rather than a roller pan. Put a painters screen down into the bucket and hook it over the edges of the bucket. Dip the roller into the bucket and roll the excess off of the roller by rolling it on the screen in the bucket. This allows you to have far less stops refilling the pan and if you keep the bucket near the wall you save time loading the roller with paint. When you are ready to paint roll a strip from the top of the wall down to the bottom of the wall and back up again. Do several strips like this and then blend in the space in between the strips. This gives a nice even coat of paint on the wall with very few missed spots.