Well, I figure when a drive is abounding in an unending amount of pending and/or offline uncorrectable sectors that the platters are done for. 
It's only when a certain (small) area goes bad and that reallocations (in relatively small amounts) remain steady over years that I'd confide in it somewhat.
It's only when a certain (small) area goes bad and that reallocations (in relatively small amounts) remain steady over years that I'd confide in it somewhat.