I was a borderline book hoarder for many years. I collected, and re-read, and moved them all with me. At my high (low?) point I had about 2000 books; they were in every room of the (big) apartment except the bathroom. Then the e-reader was born and I gradually got sufficiently confident about its stability that I allowed myself to divest masses of things that I could now get in e-form. A lot of romance and mystery 'keepers,' in particular, that I bought once in paperback I have since bought again in e-form. And a lot of nonfiction.
Many of the books I had collected were already secondary-market purchases. I would find a new author at a 'new' book store, and go out to find previously-published titles in the series (I was a real mystery hound for a while) if they were already out of print, which they often were. Then I'd buy the new titles as they came out. Always tried my best to ensure the author got paid somehow, which is why I make a point of re-buying old favorites in e-form (though usually when they go on sale, because the budget only goes so far, and I'm reading different genres now).
As I drew down the ‘dead tree books’ collection, old SF and mystery titles were traded back to specialty bookstores. Others were traded back to general bookstores. I gave tons of stuff (good-quality nonfiction, coffee-table books, bestsellers) to the Friends store at my local library. Before the last move, I straight-up gave a couple of hardcover collections to an SF/mystery bookstore in Glendale that was going through a conversion to online-only selling and was going to have to trash a lot of their old paperback stock. I traded a load of rare hardcover romances to The Ripped Bodice in Culver City.
Still have a lot of Actual Books. Some are sentimental favorites (Dick Francis - I have all of his in first US edition, many autographed) or beautiful illustrated books. Love books, always will. The oldest book I have is an 1879 complete Shakespeare I picked up for $5 at an ex-boyfriend's antique store.
As you can see, that one is in pretty rough shape. The top board is completely separated from the spine. The pages inside are sound, though I don’t read Shakespeare this way; I read it on my Kindle, or on Open Source Shakespeare.
It’s fair to say I am sentimental about books qua books. I believe civilization manifests almost entirely in what people write. There were human societies before writing, but historians don’t consider those civilizations per se. People who look at the explosion of self-publishing and say (without reading any of the material) ‘but it’s a load of crap’ are very much missing the point.
Even before writing, humans tried to communicate. Sign language and art gradually became language. Everything that is written down, from belief systems to genealogies to fiction, is born of the need to communicate. And what is a human relationship, after all, except communication?