They only have a certain working life!! Beyond that, it's all luck & the generosity of the Computer Gods.
Yeah, I realize that. Mean Time Before Failure (MTBF).
I remember reading something like 100,000 hours was considered normal.
Let's see. There are 8,760 hours in a year. That freakin' hard drive was only a little over 3 years old. That's a little over 24K hours - call it an even 30K hours before the damn thing died.
Hitachi -- Piece Of Shit hard drive. Gimme a WD (though that one will die too, but usually when it's brand new -- not afterwards after it's been "broken in."