I avoid hoarding by only grabbing things I know I'll use. With movies/shows, if I haven't used it in three months, it goes away. With music, I tend to go in cycles through genres where I'll be vibing to a given type of music for a month or two, then switch things up. So the cutoff is much longer, years in fact.

But books are a slower thing to begin with. I'm a notoriously fast reader, capable of consuming light fiction at a book and a half to two books a day. Something like the Sookie Stackhouse books by Charlaine Harris, as an example, I can zip through the entire series in under a week if nothing interferes. But even at that speed (which isn't consistent when there's heavier material), it would still take years to go through my digital library. Plus, the files are small enough that I don't have to worry about the space, so they only get deleted if I dislike something new.

The exception to all of that is some classics that I keep around just for the hell of it. Like, I have all the Hitchcock movies, but only watch any given one maybe once in five years. So I still have most of a terabyte of movies that's as permanent as possible barring redundant storage all failing at once.

Music is similar, especially since most of it is in flac format. There's some stuff I may not listen to often, but I want to keep immediately available.

Which, believe it or not, isn't hoarding. I go through things and weed out fairly regularly. It's just that after a collection is big enough, it takes longer to cycle through and use a given file again. Stuff that's used isn't hoarded.