Comment by mrjin

I have HDDs from around 20 years ago and hardly touched in last 10 years, which are still good (able to read out without any issues, random checksum are good, but not all files validated).

But my optical backs were completely a disaster. Just a little bit over 5 years, over 50% were not able to read out, ~30% could be read but content were corrupted. There might be ~10% still good but too time consuming to check so I dumped them all. I still have optical drives but I cannot really remember when was the last time used it any more.

For SSDs, I've a couple of them left in cold for around 3 years, just checked a couple of days ago, seems to be good. I'm not sure how much longer they can hold, as there were known issues with Samsung 840 serials.