Lucky me, I had only one drive fail on me in 30 years ! That sole one was a WD 1.5TB in a fan-less external enclosure. I always replaced drives because I wanted to upgrade. Seagate, WD, IBM (nowadays Hitachi), Quantum, Micropolis, Conner, anyone remember Shugart and their SASE interface (ancestor of SCSI first and later on IDE) ?
However, what I think is that a lot of people just do not provide the right conditions to their drives or do not pick up the right ones.
Rule #1: cool them drives appropriately ! Stuck in a corner of your case without proper air flow is a recipe for disaster !
Rule #2: use the right ones for the job. Green drives that tend to spin down quickly are not a good idea for a NAS or a server. Those drives will have an inordinate amount of spin up-down cycles leading to premature failure.
Rule #3: beware of external enclosures. I like the Seagate 3TB but their enclosures are terrible on the point of view of cooling, I just do not trust them. I rip'em out to use internally or change enclosure to one having an 80mm fan (I have several Rosewill enclosures, similar to this one http://www.newegg.com/Product/Product.aspx?Item=N82E16817173043
Rule #4: Never ever buy a refurb or used drive
. Would you trust your family photo collection to a drive KNOWN to have caused issues ? As for the used ones, you just don't know how they were cared for (or beaten, broiled, shocked etc...). Note that I have no problem buying other used or refurbed component, just not storage devices,