I don't wash my brushes. I put them in a plastic bag with oil medium at the end of each painting session. If you use a slow drying medium like poppy seed oil, they will stay conditioned for several days. Otherwise, if you paint every day, this is a good way to save time and boredom washing your brushes. Plus, washing brushes destroys the bristles when aggravated and exposed to solvent. When I start painting, I take brushes out of bag, take off excess oil/paint with a paper towel. This is usually sufficiently clean for a new painting session. This may not work for everyone, it depends on your level of lazy, and what kind of painting you do.