said by JRW2:said by MyDogHsFleas:D). In point of fact it is NOT a defense to pirating to say "but I bought the DVD then lost or damaged it". There is no exception on the copyright law for that situation. The legal thing to do would be to buy a new copy.
What if it is no longer is available for sale???
Then the legal thing to do would be to buy or rent a used DVD. Or if you can't find one you're out of luck.
Practically speaking, if you rented or borrowed a DVD, made a personal copy, and returned it, no one is ever going to catch you. But that is not to say it's legal.