I'm not as sophisticated as the others seem to be.

I have a couple of 16GB flash drives that I use to back up data files. One for my ebook and hobby files and one for my teaching files. (All of these files are also backed up on the main household computer in addition to my laptop.) We also have another flash drive for all our pictures which are also backed up on DVD's and stored in a fireproof safe. I'd like to say that I keep the DVD's as up-to-date as the flash drive, but I don't.