USB thumb drives have declined in price recently, making now a great time to start using them for your daily backups. Unfortunately, not all USB drives support automatic backups.
Look for devices labeled 'USB Smart Drives'; these are enabled with U3 functions or with Lexar's PowerToGo, either of which offers a self-contained operating system that lets you access the files and programs on the drive from any USB-equipped PC, without leaving remnants of your session on the system when you remove the drive. Currently, 4GB U3 drives such as SanDisk's Cruzer cost about $55, and the Lexar 4GB JumpDrive Lightning costs from $70 to $100 online. Most of these drives come with trial or full versions of backup and syncing software, but you can download a free copy of SanDisk's CruzerSync for U3 follow the download instructions) or try Migo Software's $30 Migo Personal for U3 (free trial).
Each works the same way: You select the folders and files you want to backup by clicking the box next to the folder in the outline tree. Both CruzerSync and Migo back up and sync your Microsoft Outlook and Outlook Express messages and address books, so you can access them on any computer. The backup and restore apps create mirror copies on the USB drive. You can set any of these programs to back up and/or sync specified folders automatically when you insert the drive into a USB port. Some even do automatic backups at set times if the drive remains in the USB port.