There are a lot of factors. Manufacturing process, head, lubrication, insulation, material thickness.

Nobody can give you a specific answer without a forensic teardown. I would say it’s probably the casing, refinements in head size, and noise canceling insulation inside the drive.

Drive noise measurement is always a frustrating thing to keep track of. It’s much easier to just find a solution to isolate the drive noise completely and not worry about it.

Almost no chance of that ever happening.

It’s unlikely any long term failure would be known this soon. Which is why you don’t see stats.

There’s nothing like the SanDisk SSD failure debacle, at least, known in the community.

I deal with a few family friends who have Mac and use Office. And they cannot grasp this.

Takes hours of training to explain that they have to click the offline save button, inside the save panel, to not get lost on a OneDrive.

If you mean recover the data on it, a failed drive can only potentially be recovered by a professional facility. This is why you should have multiple backups, always.

NAS drives are often the same drives as consumer. Sometimes they have more durable and quieter noise. Sometimes they use slightly different drive components/design. But realistically, most consumer 3.5-inch drives will work fine.

If drives are expensive where you live, it’s best to pick an affordable non-NAS drive with a long warranty. The more expensive the drive, the more important warranty term matters… as you are experiencing.

4TB SSDs are in the $200 USD range and have 5 year warranty now (in many regions/vendors). If you only need 6TB, you may want to go with SSD for more durability.

There’s no need to toss the drives at three years. Run drive diagnostics on them using a tool (GSmartControl, WinDLG, Hard Disk Sentinel, etc). Ideally every six months full scan, at least once per year.

Drives easily can last ten years without issue, and the odds of all drives failing simultaneously is near-zero.

Really you should keep at least one, ideally two, drives at different locations. And add an encrypted cloud backup to the mix.

Encryption doesn’t have a major drive impact. The data is effectively the same.

Now, if you set a drive to maximum encryption, and encrypt all sectors - that’s basically going to force the drive to write to every sector. This will uncover any drive surface errors, and it’s basically the most stress test-y thing you can do to a drive. If there are bad sectors, you can bet pending reallocated sectors will go up.

Again, that does not mean the drive has failed. Those bad sectors could have been there since the factory. 75 is a concern. But is not a failure.

The fail alert is that you need to zero/erase all sectors, which will allow the drive to do a reallocation. When an erase bit is sent to the sector (by the OS/erase command), that’s when it will reallocate.

This is why we tell people to have one working copy backed up to two separate backup drives (ideally in two places), and a cloud backup too.

Easily can have two drives fail.

Now, if it happened all the time, manufacturer warranties would be 3-6 months and drive makers would say “you’d better buy ten and have nine backups!”

Because… the alternative is to print everything out on paper.