convenient backup

I have been thinking about computers a lot lately and I came up with a nifty idea. Put a secure digital card in your wallet as a backup. If you look around, you probably have one just lying in a box somewhere. If you have bought a digital camera recently, look in the box and see if it came with a crappy undersized SD card. It may be undersized for your camera, but not for your word documents and spreadsheets. You can backup the most important ones and stick them in your wallet. A lot of computers now have SD card slots, so you can use them just about anywhere. You probably won't lose your wallet as easily as a USB stick. Just remember to put it back in your wallet when your done. If you're worried about theft, just encrypt the thing with a program like TrueCrypt.