Here we used the SMART report tool and it is in line with some dedicated tester.
However, I think I'm getting the picture now. You want to know if the HDD is good. Well, it is good enough at the time of the test to pass that test. This is NOT going to tell us it's good in 3 months or 1 day.
As we know, it's not a matter of if a HDD will fail, just when. You may want to collect your data and have a statistician go over it. We found that there is a correlation between hours of use, the SMART report and earlier than what some expected failures.
-> And in closing, about half the bad drives in the return pile are fine. Those are usually user errors, bad formatting or "other." I wish users were a bit more savvy but most folk want toast from the toaster and care little about how it works.
Bob