I have a shelf full of old 5 1/2" spinners that I use for archiving purposes. I used them in my Mac Pro until their warranty period was over, then moved them to the shelf where they sit unused for months on end.

My question is, will they last forever in such a situation, i.e. being plugged into a dock and run for five minutes, then back on the shelf and unused for another six months?

They still get usable readings from DriveDX. Three of them are read only, no need to write to them anymore.

What cost frugality?

With the cost per GB for bulk storage falling so well in todays market, you might ask yourself what is the value of your stored data compared to the cost of viable storage and then evaluate just exactly how much you might be risking against how much you might be investing (not spending) for that data to be safely archived.

That analysis and your decision as a result remains in your hands......

Ha! Trust me, I have multiple redundancies... I just figure rather than throw them out, put them to use.

If they are "belt & braces" backups that are not primary, then you may be choosing with an informed sense of risk -v- reward.....good luck in your use of these storage devices.

Back in the mainframe days, refreshing a drive required reading and rewriting all the data on the drive, not just powering it up. Given the underlying physics of magnetic media remains essentially unchanged, I would think the same would be equally true for your 5 ½" drives. However, you might want to read this OWC Rocket Yard blog, this follow up thread on Quora, this Forbes article and draw your own conclusion.