Keeping books for the sake of keeping books is just hoarding. And hoarding is a form of fear. Finding the nerve to throw away a book just means finding and facing the fear that drives you to hoarding.
Having cleaned up after deceased book hoarders... it's a cruel thing to do. Case after case of books, of no real interest or value, that will never get read, still sitting there rotting because OMG IT'S A BOOK YOU CAN'T THROW BOOKS AWAY.
Keep the books that are great. The books you'll read again, or use for reference in the future, or that have true sentimental value (beyond omg it's a book). I often give books away when I'm done with them - if I loved it, I probably know someone else who will love it too.
But that copy of Learn Lotus 1-2-3 in 24 Hours? Trash it. That third-run paperback of a Stephen King novel? Trash it.
I would agree about some books. But anything relating to technology should be kept. Already it is difficult to get copies of, for example, the Smalltalk-80 books. Technology reference books, and books that teach technology to people are books that should be kept, because they serve as some of the few documents that show that these things _did indeed exist_. Who, in a couple of generations, will be left to remember the BBSes, the features of Word Perfect, etc. Without this history we will be left to reinvent the wheel constantly.
I don't agree there. Classics should be kept - stuff like the Dragon book (compiler theory), Refactoring, Knuth's Art of Computer Programming series, etc. But frankly, most books about our industry are trash - throwaway material that will be as obsolete as buggy whips, in a lot less time. But the good books never become obsolete.
I recently picked up a copy of The Mythical Man-Month, from 1975. There's hardly a line in it that doesn't still apply today.
There was an interesting time in the mid-90's when computers and internet were gaining some steam, in which used book stores would pay top dollar for any computer related book, no matter how niche or obsolete. They've wised up considerably since then, though.
Why even that? Why should I spend an evening scanning 400 pages of junk? That's worse than just keeping the book. Trash is trash.
I could spend that time finishing Accelerate (potentially a timeless classic), or Openshift in Action (doomed to be dated and irrelevant someday, but immediately useful to me now). Those are genuinely useful to me. Hoarding is not.
Having cleaned up after deceased book hoarders... it's a cruel thing to do. Case after case of books, of no real interest or value, that will never get read, still sitting there rotting because OMG IT'S A BOOK YOU CAN'T THROW BOOKS AWAY.
Keep the books that are great. The books you'll read again, or use for reference in the future, or that have true sentimental value (beyond omg it's a book). I often give books away when I'm done with them - if I loved it, I probably know someone else who will love it too.
But that copy of Learn Lotus 1-2-3 in 24 Hours? Trash it. That third-run paperback of a Stephen King novel? Trash it.