We have approximately 750 books. No idea how we got this many, they just kind of built up. The kids alone have over 100. We gave away 250 a few years back and it barely dented our shelves.
Anyhow, we are very quickly getting sick of not being able to find the book we want, so I am pushing for a better system. We have a vague thing where books tend to be near where they were last read, so the kids books tend to be near the toys, the trashy novels and browsing books tend to be in the bathroom, reference works are in the front room, feminism, history, politics and sociology tend to be in the garden room for some reason, and literary fiction has a habit of being in the bedroom. Computer manuals and buisnessy books are near the computer, comics are high up or the kids mess with them, and outsize tend to be in the shelves under the tv.
This can not continue.
However, my MIL (who is a trained librarian) thinks it hilarious that we would try to impose order. I suppose our shelves are nothing after a career dealing with proper libraries, but still.