Windows user here. I use the built-in robocopy utility to sync files to one of 2 external hard drives. One hard drive stays at work, the other at home, and I sw

Windows user here. I use the built-in robocopy utility to sync files to one of 2 external hard drives. One hard drive stays at work, the other at home, and I switch them periodically (usually, right after downloading new family photos onto the computer). With this method, a virus or something like a fire that only affected one location would not be able to take out all copies of my data and, at most, I'd lose the most recently backed-up information. It's not 100% bullet-proof, but it's good enough for my personal purposes.