Has your external HD seen better days? Is it suddenly starting to make strange noises that don't seem quite normal? Maybe it is no longer "mounting" on the desktop when plugged in and you have to finagle it 2-3 times to get it to recognize. Chances are your HD is on the fritz and you better replace it before the data is lost. Personally, I keep music, photos, videos, and even important documents on my external HD. Most importantly, I run Time Machine backups to my external HD. These are important devices for many computer users but normally viewed as a necessary evil versus a necessity.
If you're in the market for a high quality external HD, small and portable, and not looking to spend a fortune, I hve the deal of the day for you. It does run out in appox. 24 hrs so act fast. The Western Digital "My Passport" 1.5TB USB 3.0 drive is available right now from Groupon for $83.99. It is "refurbished" but comes via the manufacturer with a 6 month warranty with free shipping and returns. You can't beat this deal as even Walmart (generally best prices I find locally) has it listed at $100.99. Don't delay....your data is too important!