I have a half dozen hard drives for offline/offsite backups, mostly Seagate Barracuda between 1TB and 3TB, mostly 2-4 years old. Most of them have only been spun up between 20 and 100 times. Most have never been filled, I do a full format when I get them then add data as I create it.

Almost all of them are getting SMART errors, especially reallocated sector counts. Should I immediately replace a disk with a reallocated sector count above one? Or only if it climbs? It's a little difficult to track them, since the hard drives are usually offsite.

My internal disks are mostly Seagate, with one WD drive, and they're used every day. They spin up, spin down, probably dozens of times a day. Those drives rarely have problems, though one did generate a SMART warning so I replaced it.

Is any brand/model of drive more suitable for use as offsite backups, rarely spun up? I think i'd try western digital, but do I go black (have one, good, fast, 5 yr warranty), red (nas focused, 3 yr warranty), blue and green not so interested.