several things to note about external hard drives.
1. in a Windows environment, these drives are not seen like regular Hard Drives because they are not attached to a normal SATA or PATA channel. This means that they will not "spool down" when not in use like regular internal drives will based upon the power settings for the computer.
2. These enclosures DO NOT vent as well as a good computer case and thus tend to run the temperatures of the drives when operating much higher. Even the units with fans will do so. It's best to get an aluminum enclosure if you can, as the metal will help dissapate heat where the plastic will insulate it.
3. Most of the Purchased external drives only come eith a one year warranty whereas most internal drives have either a three year or five year warranty. See #1 and #2 for why.
If you want to extend the life of an external drive, simply unplug it when not in use or turn it off if it has a switch.
This will cause it not to spin, not to generate heat, and will GREATLY prolong the life of the drive.
Oh, and for anyone using the MyBook world edition, apparently, WD has blocked thre ability to stream most media files through it's "web access" portion recently.
Lucky you.....