That's not true, but I do try to have a book on any subject that I want to know all about - though actually finding time to read them all is another matter ...
I used to buy a book from Waterstones every time I went anywhere near a Waterstones shop, then Amazon tempted me to buy a used one, perhaps one or two every week very cheaply indeed (many at 1p plus £2.80 postage), then I ran out of space.
These days I check into one or two charity shops that have good selections of used books and probably find a useful one every week or so. I recently found a brand new book on photography for £3.
I've just counted up my fishing books and realised that I have too many to admit to including 2 copies of the same book ...
I also need to throw out books that I will never read ...