[kissiel]

That sounds very optimistic. Do you have any data to back that up? Is it hot or cold storage? I understand, that the breakdown of magnetic field is indeed slow, but the HDD as a whole is not as sturdy, I think - you need to spin the platters, control the heads and so on.

[spwa4]

That's true. Perhaps I should say that data on hard drives will remain recoverable, not available, for a century.

Data on CDs/DVDs should remain recoverable for millenia (properly stored, even readable). Another advantage: CDs/DVDs can be duplicated with only analog tools maybe 10 times to further extend that (obviously not writable CD/DVS). And if we were to glue cd's top-to-top, that could be an easy hack to 10x that, which would even work for (re)writable CDs/DVDs.

(Re)writable CDs/DVDs should remain readable/recoverable for centuries too. Probably not millenia.

https://www.easeus.com/resource/does-ssd-need-power.html

TLDR: SSDs keep data for "minimum 1 year" when used as archival storage (of course specific models have been caught losing data in as little as 3 months). Keeping the SSD powered on regularly should increase that, but only to 2-5 years if you want to be on the safe side.

[buttercraft]

> Data on CDs/DVDs should remain recoverable for millenia (properly stored, even readable).

If by "properly stored" you mean in a cold, dark vacuum, then maybe. Otherwise this is not true in my experience. I've had CD's in temperature controlled storage for 25 years and about 1 on 10 are unreadable. It's my understanding that they oxidize. In theory gold CD'S are immune to that.