The woman at my local yarn shop says - every new pattern you do should have something in it you haven't done before! Keeps it interesting! Which is true. I'm learning to have several projects on the go - some that is 'mindless' - I can do it in the car, while watching TV etc. And something that requires me concentrate, count, mark stitches, keep the pattern in front of me. So depending on my mood & circumstance I can pick up what suits.