> What this seems to suggest is that as a drive gets more "worn out", its data retention gets worse.
This is what informal tests (i.e. via scrubbing/resilvering the drive after leaving it powered off for a long time) have found. Retention/data remanence is remarkably good for a drive that has been written over just once, and quite bad (i.e. you start seeing bit errors) for one that's almost worn out. This is actually very good news for the EEPROM-like use case where rewrites are quite rare.
(Note that "almost worn out" in this case can mean going far beyond the formal total-data-written rating of the drive. We're talking the range where the hardware itself is about to croak.)
This is what informal tests (i.e. via scrubbing/resilvering the drive after leaving it powered off for a long time) have found. Retention/data remanence is remarkably good for a drive that has been written over just once, and quite bad (i.e. you start seeing bit errors) for one that's almost worn out. This is actually very good news for the EEPROM-like use case where rewrites are quite rare.
(Note that "almost worn out" in this case can mean going far beyond the formal total-data-written rating of the drive. We're talking the range where the hardware itself is about to croak.)