I used to loan cds to a few trusted friends on occasion. However, even my trusted friends don't care for them as methodically as I do. The discs would come back with scratches all over the bottom, as if they'd spent time out of their jewel cases/not in a player or were played in car stereos. They'd play fine, but damn!
Once a trusted friend borrowed and scratched one of my Willie Bobo records, right through the track that I told him to listen to.
More recently I've been making compilation cdrs when I want to share tunes. No more loaning.