This question already has an answer here:
If I store information on a USB Flash drive and hardly ever read or write to it, how long can I expect the information to be retained?
I'm referring to natural de-magnetization and anything similar. Not to "read disturb" etc.
Thanks for the link. The question there is indeed similar to mine. But unfortunately the answers there just assume that the answer is: more than other limiting factors. But is that true? This needs some backing, does it not?