I love the ways these are tidy and easy to understand. I fill lots of little notebooks with collages but usually go way over the top with painting over them.
With lots of books I work over I've kept them because I like what they are, and am often hesetant to work over them, so I try and keep enough of the original to preserve the qualities that first attracted me. The 'I broke them all apart 87' is one I didn't think I coud add to, so I've just preserved it...