All I can say on this, is that WD likes to "unload the heads" after 8-seconds of inactivity, and then place the drives into a lower power state. They call this the "Idle 3" state.

If you are just using these for backups, then no worries with the factory setting.

The problem, is that drives are usually rated for a finite number of load/unload cycles -- somewhere on the order of 100,000 - 500,000.

When one of these drives is used as a general purpose system drive, the load/unload counts can very quickly rise into the tens of thousands over the course of a couple of weeks.

So, WD used to make available a utility, WDIDLE3.EXE, to change that value. Of course this is all vendor-proprietary nonsense, instead of simply using the existing standard SATA power management commands.

WD now make it harder to obtain their WDIDLE3 utility, but web pages from them still suggest it is available upon request.

I googled for it here, and found wdidle3-1.03.zip for my 1.5TB drive. I used this to reset the "idle 3" timeout from 8-seconds to 30-seconds on my own drive, at my own risk.

WDIDLE3 /S30

There's a help file in the .zip archive explaining the various command options.

Cheers