If the data doesn't matter: Put it on one drive.

If losing the data would cost you minor downtime: Put it on two drives (or storage arrays of some sort) in two locations.

If losing the data would cause major downtime: Put it on three drives (or storage arrays of some sort) in two or three locations.

If losing the data would cause life-disrupting issues for multiple people: Put it on as many drives as possible/feasible (or storage arrays of some sort) in enough locations that you can sleep well at night.

Edit: weird thing to get a bunch of downvotes, but you do what you want with your data

Just throwing this out there for anyone shopping for storage drives. BackBlaze does a pretty good regular writeup on the drives they use and how they perform, how reliable they are, etc. It's very informative and a fun read (if you're into nerdy stuff).

https://www.backblaze.com/blog/backblaze-drive-stats-for-q2-2023/

"I trusted all my important data to a single point of failure and now I'm screwed".

So, yes, I respect that SanDisk's drive may have a manufacturing defect and that sucks but they have to share the blame for this. Seriously, drive mirroring is a thing and every single OS supports it out of the box. A proper RAID system is a thing and even better. Adding duplicate storage, be it cloud, another NAS or backing up to tape is even better still. It's the 21st century, you should know that by now if your literal job is based on storing data.

3tb of unprotected data? And it’s the 2nd time it’s happened? Raid1 has existed for a few years and seems pretty reliable.

NAS w/ RAID...

It's funny how the loss of storage space can be valued diffently. If it's 3TB of of video footage for a newspaper, that's weeks if not months of work and money lost. But it could also just be the last 3 Call of Duty's with patches.

I use mine for desaster recovery.

Using tineshift to take hourly snapshots of my laptop computer.

I don't think my laptop and the drive fail at the same time so I think my use case is safe even with these risky drives.

What is the advantage of using this over an USB to SATA adapter?