I never delete anything either. Many times I've gone back to an abandoned project, seen it in a new light, and finished it; often the result was completely different to what I originally intended. I kept going back to Missing over a period of about three months. One piece of music I worked on was set aside for ten years before I worked out how to finish it. The piece I wrote for my son's birth still hasn't had its final mixdown, and he's now fourteen. I think you need to be able to recognise when something isn't working, and continuing to work on it is dragging you down; but at the same time, be aware that you will think differently in the future. Your skills will improve, your perceptions will change, you'll be inspired by as yet unknown sources. You can never tell what will be valuable, and what will be trash.