I’m thinking about getting one for several purposes, primarily for portable software, some certificates and keys, and a few backups. Since it won’t be powered off for more than a few days or weeks and won’t experience heavy writing (although I plan to use Veracrypt and that may cause some stress)
How long can I expect it to last? Obviously there will be backups, but I also don’t want to lose anything on it as much as possible.
Not long enough is the true answer.
If they just sit around on a shelf, they’ll still slowly lose charge until one day the data just isn’t readable. If they’re on a keychain, I haven’t had one last for more than two years, and I don’t get my keys wet or anything.
Even if you take great care, the data will still slowly corrupt because of how nand flash works. Unless you’re rewriting all data every couple years, never getting it wet or exposing it to much, etc, they’ll all fail sooner than you’d ever hope.
That’s on top of any chance at physical damage. I wouldn’t trust any modern thumbdrive beyond an immediate need to carry data from one place to another.