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When it comes to making decisions about putting data on DVDs, says special correspondent Dawn Chmielewski, you have every right to be confused. There are five recordable formats competing for your money. Are they compatible with one another? Not always.

The first question to think about is whether you want discs that you can erase and reuse. Those so-called rewritable discs--DVD+RW, DVD-RW, or DVD-RAM--tend to have the most compatibility problems. And they tend to be harder to work with. They're also more expensive than the so-called write-once discs that go by the names of DVD+R and DVD-R. Those discs are cheap, and they're relatively compatible. And the good news is that, increasingly, you can find machines with so-called DVD+/- drives, which can handle both.

You think you're out of the woods? Not so fast. There's a new breed of discs and drives called "dual layer." They hold two layers of data on the same side of the disc, which can almost double the capacity. But older drives can't read dual-layer discs. On top of all that, they're the most expensive of all.

If you're not likely to move the discs around much--like when you're using them for backup--it probably won't matter which kind you use. Whatever's compatible with the drive in your current machine should do just fine. After all, that's the drive you'll probably be using to restore your data if it disappears from your hard drive.

But if you want to ensure that family members can watch home movies of your child's birthday party or your last vacation, you're better off burning the disc as a DVD+R or DVD-R disc. They won't work every time in every player--hey, the discs the producers send us for this show don't always work in our players--but they'll give you the best chance of not getting a phone call that says, "Hey, that disc you gave me won't play in my machine!"

Back at the Duo's home desk, Steve and Angela are darned grateful that Dawn, not they, ended up explaining that mess. Despite the confusion, though, there are advantages to backing up to DVD. Not only are the discs cheap, they can last a long time--several decades in theory, though nobody really knows for sure. And they're portable, which means you can keep one backup near your machine and store another somewhere else, like a safe-deposit box. If you have a fire or flood, you'll know that most of your pictures of that new baby are snug and warm.

The disadvantages? Well, DVDs are relatively slow, and since they don't store as much data as the drive in your machine, you may have to be physically present during a big backup so that you can swap discs in and out of the drive. There's that incompatibility factor that Dawn mentioned. And the Duo have seen enough flaky discs to suggest it's essential to have your backup software verify each disc to make sure what you thought you copied onto it actually got there. Which slows things down still further.