Time Machine and external HDD

So I'm hoping this is 1) in the correct area of the forums and 2) somebody out there has some personal experience to give me advise.

Just started using Time Machine because I recently installed Windows 7 w/ bootcamp for SWTOR soon. Anyways, Ive been using a Hitachi 500gb "SimpleDrive Mini" (500CF model) external HDD for the back ups. It was set to hourly back ups w/ time machine.

Worked great for about a week then I came to my desk to see the HDD icon missing from OSX desktop and the drive was active (light on) but only thing it does is produce a constant "clicking" sound, approximately 1/2-1 second intervals. Disk doesnt show up in Disk Utilities and unplugging/replugging does nothing.

I'm going to Best Buy to pick up my WD My Book 1TB external HDD that arrived today for $50. But i wonder if anybody has had similar issues with specific brands/models of HDD's?

Also, does changing the back up times affect the longevity of a HDD used? Also, I believe I restarted the computer multiple times while installing/setting up Windows w/ bootcamp WITHOUT ejecting the HDD. It still worked after that for a day or two...but may have caused issue??

Sorry for a long post, but I dont want to pour money into new HDD's every month (or week lol). THANK YOU for any help!

Sorry, but additionally I'm using this with Snow Leopard 10.6.8 on a 27" iMac w/ Core 2 Duo proc.

Hard drives are not only electronic devices, they're also mechanical devices; and as such are subject to failure. I've seen brand new hard drives right out of the box that were DOA.

Be sure to contact Hitachi as the drive that died may be under warranty. If it is, Hitachi will issue a RMA and replace the defective drive with either a new one or a refurbished drive.