The USB drive time bombI destroyed an iBook drive by basically using it like a server drive for 3 years. No hard feelings, I flogged that beastie.
...In a typical business-computer situation, where the skinflints in the purchasing department have made sure that every PC in the place is short of physical memory and so flogs its drive non-stop for eight hours a day, a substantial fraction of those drives can be expected to last two years or less. Three is definitely pushing it. Support people in such companies are used to doing drive replacements, and would probably have to do significantly fewer if the computers had more RAM.
People with the misfortune to have bought a base-spec Dell desktop are in the same situation, but so are a lot of geeks, who make up for their ample system RAM by spending a lot more time in front of the computer doing stuff that hits the disk. Heck, just downloading all that video will stop the disk receiving it from ever spinning down.
The way you make consumer drives last is by not using them. If they're spun down in standby mode, they're not wearing out. Even if a drive's kept in an anti-static bag in a cupboard, it won't last forever, but it's usually the physical components like the spindle and head assembly bearings that kill a drive after two years. When they ain't movin', they ain't wearin'.
Getting hard drives to spin down on any modern computer is, of course, easy. You can set the spin-down time to a really aggressive laptop-on-batteries five minutes or so, if you like. Consumer drives spin up fast (server drives don't), so there's no huge performance penalty to pay for doing that.
But if you're using USB drive boxes, their own little bridge interface is what decides when the drive spins down. Or, more accurately, if the drive spins down....
I haven't paid enough attention to spin-down in external drive units. Mea Culpa. Now we all know better ...