Assume anything you can buy has a shelf life and set a yearly reminder on your calendar to copy forward stuff more than five or so years old, if those files are of significant value to you. Or for the documents, print them out—paper has better longevity than any consumer-available electronic storage.

That being said, quality optical discs are probably the best option in terms of price to longevity ratio for the average person right now. Just keep in mind that they are not guaranteed to last forever and do need to be recopied from time to time.

(I have yet to have a DVD fail on me, but I keep them in hard plastic jewel cases in climate-controlled conditions, and I’ve probably just been lucky.)

You might be interested in git-annex (see the Bob use case).

It has file tracking so you can - for example - “ask” a repository at drive A where some file is, and git-annex can tell you it’s on drives C and D.

git-annex can also enforce rules like: “always have at least 3 copies of file X, and any drive will do”; “have one copy of every file at the drives in my house, and have another at the drives in my parents’ house”; or “if a file is really big, don’t store it on certain drives”.

I use LTO magnetic tape for archiving data, but unfortunately the tape drives are VERY expensive. The tape itself is relatively cheap though (this is a 5-pack at 12TB uncompressed, 30TB compressed per cardridge, totaling at 60TB uncompressed, 150TB compressed. This is a lot cheaper than hard drives, and lasts for much longer), has large storage capacity and 30+ years of shelf life. Yes, I know, LTO 9 has come out, but I won’t be upgrading, because LTO 8 works just fine for me, and is much cheaper. The drives are backwards compatible by one generation though, e.g. you can use LTO 8 tape in an LTO 9 drive.

I am using https://duplicati.com/ and https://www.backblaze.com/ ( use their b2 cloud storage its variable and 6$ a month for 1TB or less depending on how much you use) run a schedule beckup every night for my photos. It’s compressed and encrypted. I save a config file to my google so say if my house and server burn down. I just pull my config from google then redownload duplicati and boom pull my back up down. The whole set up backs up incremental so once you do the first back up its only changes that are uploaded. I love the whole set up.

Edit: You can also just pull files you need not the whole backup.

There isn’t anything that meets your criteria.

Optical suffers from separation, hard drives break down, ssds lose their charge, tape is fantastic but has a high cost of entry.

There’s a lot of replies here, but if I were you I’d get last generation or two’s lto machine from some surplus auction and use that.

People hate being told to use magnetic tape, but it’s very reliable, long lived, pretty cost effective once you have a machine and surprisingly repairable.

What few replies are talking about is the storage conditions. If your archive can be relatively small and disconnected then you can easily meet some easy requirements for long term storage like temperature and humidity stability with a cardboard box, styrofoam cut to shape and desiccant packs (remember to rotate these!). An antifungal/antimicrobial agent on some level would be good too.

I use external hard drives. Two of them, and they get rsynced every time something changes, so there’s a copy if one drive should fail. Once a month, I encrypt the whole shebang with gpg and send it off into an AWS bucket.

3-2-1 rule with restic. Check it out.