It may be helpful. Consider online backups for your important digital documents

[Garth Wilson]

Answering several things above without quoting them:

USB thumbdrives and and SD cards do not need to be powered up periodically. They store data in flash ROM, not battery-backed or capacitor-backed RAM that needs occasional recharging. Flash is a type of EEPROM, and its data-retention time is usually forecast to be a couple of centuries, unlike EPROM which was only guaranteed for a decade but I've never seen it lose data even after three decades.

Don't use home-writable DVDs. They don't last. I had heard this, but it really hit home in 2014 when I was reviewing two-year-old pictures of our son's wedding and found that some of them were already becoming unreadable. Right away I made sure to get the remaining ones onto a hard disc.

I do like the idea of printing the most special pictures (professionally, not on a home printer or 1-minute service at CVS which fades badly in only a few years). Our daughter-in-law's father is quite a shutterbug, yet when I asked if we could see pictures of our DIL and her siblings taken when they were kids, he had thousands of them and they were on drives here and there, unorganized, and it was difficult to find the good ones, so we didn't get to see any. A paper photo album would have been welcome.

If I were to use a cloud service to back up my stuff, I would definitely want to encrypt it so neither Big Brother nor anyone else can get nosey and label us one way or another, harrass us, limit our rights, whatever, for holding beliefs that "offend" some snowflake of BiBro itself.

Our DIL uses an external hard disc interfaced by USB to back up her laptop's hard disc.

At home, our son (not the one mentioned above) set up a server that automatically does a backup every day of all the PCs in the house that are on at backup time. The server has two identical 2TB hard discs, and the first one is backed up by the second. I don't know if that backup is every day, once a week, or what. When he was still living here, he would then back up the backup periodically with another hard disc in his room. The server is in the garage which is a separate building and far enough away that one building could burn down without affecting the other.

He also backs up my website (which is hosted thousands of miles away on a virtual server whose connection speed is at least a hundred times as fast as ours at home), and I occasionally back it up as well, even putting it on SD card.

When I'm done with a software project, whether for work or home, I always print out the source code. Then if everything digital were to fail, I'd have to type it in again, but that's way faster than developing it again.