I have posted several times recently about parts of my library. I have accumulated a lot of books. In the last few years I've been giving away more than I have been buying and, when unsure whether I will want to re-visit, getting the Kindle edition rather than the physical book. Many that I have discarded have gone to friends or to the Madison Public Library. The library sells them to support its work. I've been trying to narrow what I keep down to things I may want to re-read or at least use as reference (although I am much more likely to use Google for that these days).
My most enjoyable leisure reading has always been mysteries. Far more of what I've kept of them have been from an earlier era — many from a time before I existed. This is not the complete collection — there are three more shelves.