I've kept all mine through the years believe it or not. I have bookshelves full in my attic. I'm not sure how many I have but I have all the numbered Pocketbooks, most of the Bantam books from the 1970's (I still need a couple of the Star Trek Logs by Ballantine books) and pretty much every book released since 2005. I am missing a few from the period when the numbered novels stopped and 2005. I prefer paperback/hardcopies over E-Books, but will by E-books if it is the only version available.