What do you do with your roller and your cut-in brush in between paint coats? Wash them? If so, you are wasting a whole lot of water! I wrap mine up in a plastic bag and put it in the refridgerator. It will keep several days that way (if you're like me, and with the kids around sometimes I just don't get around to finishing it when I want to.) Then you can take out your brush and/or roller and continue painting! I'm honestly not sure if this is a "normal" practice for a lot of people. But if you do any painting, you should try it! When your done with your roller, wrap it back up in the bag and toss it! Of course, you should wash your brushes.
Pros: Saves a LOT of water and paint from going down the drain. It also saves time and energy.
Cons: It requires the use of a disposable plastic bag. Requires some fridge space.