I'm used to this sort of reversal from medical science, not computer hardware. Google research says we don't undersand hard drives all that well.
1. They're much less heat sensitive than we thought. Once a drive is "mature" heat doesn't have much of an impact on lifespan.
2. After a drive emerges from its infant mortality period, it's not much affected by use. So contrary to everything I've ever written, there's no great need to spin down a USB attached drive.
3. If a drive is found to have any defects on initial testing, it is 10 times as likely to fail as a defect free drive. I'd read that Apple selects server drives by buying conventional drives and tossing out any that have defects. Makes sense. If you buy a new drive, and find a mapped-out defect (may need special software), maybe you should consider returning it ...