Rereading is essential. But since I tend to be very hard on the books I enjoy, I stock up on copies of my favorites. Often I'll buy a trade paperback reprint of, say, a classic SF novel, then pick up older editions at used bookstores and public libraries (locals: Doylestown is good. Warminster is better - 10 cent Vonnegut paperbacks). If y'all are lucky - or ask nicely - the well-loved, semi-worn modern editions will be released!
Incidentally, I released one book in Chalfont a few years back (Adventures of Kavalier and Clay), and it was never heard from again...
For your reading pleasure (or disgust), I have a short list of repertory novels on my Myspace page.
There will be a test.