"Quick little paintings of still life objects are a training tool for artists. They keep the eye alert to value, color, and draftmanship. Additionally, they are pure pleasure!" --- SFG
One of my teachers had a saying that has stuck with me and served me well for many years. He said, "Paint every day and you will get better. Paint every-other-day and you will stay the same. And paint every third day and you will get worse."