The Assistants on the show I am working on are doing a real cool trick. After they make a DVD output, they load the DVD onto the editorial computer that has a external hard drive that contains back-ups of all their DVD outputs.
What they do, is open up the DVD and option-drag the Video_TS folder into a folder on the hard drive with the sequence name and date (make sure this folder does not have spaces).
Then, if you need to make another copy down the road, you open up toast, drag that folder on the back-up drive into the toast window and burn your DVD copy (which is why you want this folder not to have spaces, or the disk will be corrupted). Of course, if you need another burn in (say it is going to another person), you will still need to make another output. But this is a very nice trick to know.