I am someone who loves to use my sketchbook as a means of experimentation. I am able to make collages that aren't completely refines, or paintings that aren't fully rendered, but it still is a way of expressing myself and trying new ideas.
I have so many sketchbooks, and I don't have the heart to get rid of them, so they end up filling any open shelf space I have. They are like time capsules of myself and the creative process I have gone through.