As a carpenter, many co-workers would ask to borrow my tools, always saying "i'll treat it as if it were my own". My reply was always, NO you will treat it like it's mine, and take care of it. I stopped loaning tools, they are too costly to keep replacing. I have a loaner 35mm camera, it's a POS but works just fine. After a short tutorial, the borrower skips on their merry way knowing how to use and care for it. If it were to be damaged, I wouldn't care, I have zero money invested in it, I found it while cleaning out a house I purchased. As for my kids borrowing my stuff, I buy them their own tools and cameras so they leave mine alone(except my youngest, she takes great care with my gear).