There are so many factors for me...First is how I am feeling, then do I have other pressing things I need to do. When I am feeling good I try to sew at least every other day. Then the in between days are for other fun things like laundry and housework.
Sometimes when I am in the middle of a project, I try to spend some time every day on it. I just have to pace myself so I don't overdo on any day. If I do I pay for it and lose time sewing ;-)