Ever let someone borrow something and they break it? RealSimple has an interesting post on borrowing, and what happens when something goes wrong:
Borrowers do have an obligation to replace items they break or lose, says etiquette authority Anna Post, who leads business-etiquette seminars for the Emily Post Institute, in Burlington, Vermont. That's why borrowing -- or lending -- expensive items is not a great idea.
I've unfortunately had this happen to me, mostly with books being lost. If you've let someone borrow something and it didn't end well, let us know how you handled it (or wish you would have handled it) in the comments.