Right now I'm in the process of burning DVDs of ALL of my photos. ALL of them. I"m about to start disk 6, and I'm sure I'll be up to about 10 before I'm done. Yikes! In my defense, I'm burning the photoshop psd files, as well as the RAW photos, and scrapbook page scans. I've had "back ups" here for years, but it's time that I got a "real" back-up done & over to my parents' house. Just in case.
My general rule of thumb is that I have photo files in two places. On my camera & computer. And if I want to delete them from my memory card, I burn them to a "junk" dvd. One that doesn't necessarily have any edits done, the file names aren't necessarily correct, maybe it contains the bad photos. Whatever. Just in case the computer crashes.
But what if. What if our house is destroyed, or burglarized. I really ought to have a back-up at my parents. A tip I read recently was to make the back up & then test it out on someone elses computer. Because IF you need that back-up, you won't be opening it up on your computer.
The other tip I'd like to share, since many of us are concerned with the archival-ness of the dvd: make a new copy every five years. Then there shouldn't be any stress over what program created the files, how long the disk will last, whether you wrote on it with a sharpie, etc. I figure it's a small investment in making sure our photos are around for a LONG time!