Re: So mirror them
I use both types here, a lot. I've become more comfortable with SSDs now, but I do tend to overprovision them, and back them up. I also do that with spinners. So far, I've had really good luck both ways. I've had some fail, but that was apparently a quality control issue with an SSD from Crucial, supposedly due to shipping some stock from a company they'd bought that had problems or similar.
The drive had gone into total CMOS latchup - a flaw probably in the controller (acted like a short on 5v) but it was temperature dependent and I was able to recover *from that drive* which was a bit better than using the backups I also had.
The one spinner I recently had issues with was a seagate 2 tb 2.5" drive that started to have some vibration after about 2 years in 24/7 use for a home weather database - lots of writes. It's never failed, but I switched it out and now use it for archival backups. I think the bearings were starting to go bad after spinning that long. It was never spun down in use.
The only drives we had fail here - and we lost data, also the only time ever, were IBM deskstar drives, which had been backing up one another on workstations in an off grid system that had no central server - all was peer to peer. When they all failed within 3 days of one another, we lost some data, and they were right jerks about even giving us new drives, just before they sold that line to Fujitsu. They insisted we run their diagnostics, which passed (it had been warm but had cooled down by the time that happened) - but our data was gone anyway.
We used them as targets on the shooting range, most satisfying, along with a few old floppy drives.
I've had issues with USB flash more or less burning out if used constantly for writes on say, a raspberry pi. Never with a real SSD. When I set things like that up, I make a tempfs to do those usually not worth it logging writes (once things are setup, do you really need to know every time something else on your lan reads a database or connects via samba, or hits a local webserver?).
Long story short - our single actual data loss, and it was without warning, was spinners. In the decades from 1980 on up. Probably shouldn't use the same brand, model and age for backups as the main show.