I've done this numerous times. I also rarely lend out books. But i have many more than 2 bookcases. Two different books, I've ended up buying twice. One of the two copies I've been taking with me traveling, so it didn't really hurt to have a second copy. When I lose something, I'm likely to find it when I least expect it, in a fairly unlikely place. Lately, it doesn't help that everything in our house got packed up to install new flooring. I'm still finding stuff I though was lost forever.