[userbinator]

When I was still relatively familiar with flash memory technologies (in particular NAND flash, the type used in SSDs and USB drives), the retention specs were something like 10 years at 20C after 100K cycles for SLC, and 5 years at 20C after 5-10K cycles for MLC. The more flash is worn, the leakier it becomes. I believe the "few weeks" number for modern TLC/QLC flash, but I suspect that is still after the specified endurance has been reached. In theory, if you only write to the flash once, then the retention should still be many decades.

Someone is trying to find out with an experiment, however: https://news.ycombinator.com/item?id=35382252

[mrguyorama]

Indeed. The paper everyone gets the "flash loses its data in a few years" claim from wasn't dealing with consumer flash and consumer use patterns. Remember that having the drive powered up wouldn't stop that kind of degradation without explicitly reading and re-writing the data. Surely you have a file on an SSD somewhere that hasn't been re-written in several years, go check yourself whether it's still good.

Even the utter trash that is thumb drives and SD cards seem to hold data just fine for many years in actual use.

IIRC, the paper was explicitly about heavily used and abused storage.