Do you keep a database of your book collection anywhere? An online website? An excel spreadsheet? A handwritten paper journal?
Not really, although I do have a Goodreads account, so I do kind of keep track of things that way.
It would probably be a good idea for me to use something to keep track of what I already have–on more than one occasion, I’ve come home from a bookstore to find that one of the books I bought was already sitting on my shelf. The problem is, though, that I’m positive I don’t already have it, so…a list would be useless if I don’t even consult it because I don’t think I need to.