Yep. I feel your pain. At first we hung onto old books and manuals because, well, maybe someone would ask us to look at old code, right? At least that's what we told ourselves. But, really, DH and I are bibliophiles. When we got together, the biggest issue we had in combining households was all the books. We purged a lot back then (both IT and non-IT).
We retired in March. It was freeing recently to get rid of the IT books. We still have tons of others. DH has the largest quantity of literature. I have a thing for how-to's of every kind (especially cookbooks, gardening, home improvement, dog training) as well us understanding people/society (history, biography, women's issues). We're in the process of a complete home remodel, and during this, have to move things from a room being worked on to a room not being worked on from time to time. This was the real tipping point that caused us to purge the IT books. It was stronger than nostalgia.