I draw a line between collecting books and having a reference library for modeling. At various times in my life I have been a book reviewer , specializing in military and aviation subjects, among other things, and I've managed a used and rare book store, and now I'm back to reviewing books. But now I mostly only get books we commonly use for modeling references. I find that of those, there are about a fourth of them that I would ever use for my modeling projects. The rest, I make a separate place for. I learned the first time, when I was working for a very large daily newspaper and got up to fifty books a week, that many more books are printed than really need to be, or deserve it, for that matter.
Not that I'd lke to go back to having to buy all my modeling references. I am a poor freelancer now, and these books are pricey considering a book of less than 80 pages can run over twenty bucks. But collecting them, as well as magazine, just to have them has no appeal to me as it once did. I too once had every FSM, and almost every Wing and Airpower, but couldn't find a single one I needed in the whole stack in those pre-index days. Same for Squadron-Signal publications. I would find the perfect reference in my stash only after the model had been finished for two months.
You should have seen the tears I wept when I lost them all in a fire, along with my models and everything that goes with building them.
Now I keep things manageable, and try to keep a lid on my natural, childish greed when it comes to my toys. But they pile up somehow. I am reaching the point where I'd like to give or trade books to other modelers who can't afford to buy them. For example, I don't build armor, only aircraft. but yesterday I got a book on M2/M3 halftracks. I get books on modern warships, but I only build sailing ships. These books get brief reviews, as is my obligation, then go to the "in the way" boxes.
Tom