I keep most of the books I use all the time in the place where I do most of my work (home office, 3 1/2 bookcases), but after a while they multiply and start to double up on the shelves. I have other bookcases in other rooms, but so far they have defied any sense of order.
My attempts to organize them would go like this. I would pick up a book, or several, and then realize that I had Big Decisions to make:
1. Shelve British and American and other lit works together?
2. Shelve criticism with the books or by itself?
3. Shelve books according to interest and taste or alphabetically? For example, do I group about ten of them together because they are in the category "obscure women's autobiographies that I really, really want to read some day" and I will otherwise forget about/lose them if they're in the alphabetical section?
You can guess the next step: I pull a book off a shelf, and, while pondering the imponderable, I sit on the floor and start leafing through it, leaving heaps of strewn books that I'll eventually shove into any old shelf just to get them off the floor.
But today, faced with the prospect of Thanksgiving company, I worked on putting books on shelves where I might have a chance of finding them again. There are still lots of them in heaps on the floor, but hey, the night is young and the people coming for Thanksgiving won't be here for another couple of days.