I doubt that any of us will be able to reformat a hard drive enough times to make it fail from that alone. That being said, all of us are going to buy an unlucky drive with a short life span at least once each decade.
If your hard drive is making noises, or if you haven't done a backup in a while, the simple thing to do is simply copy your documents, photos, and other important data to DVD or an external hard drive.
Typically, I don't waste my time making backups of applications, as they can be reinstalled using your existing original media. I only want the data - the stuff that I created and have no other copies of. Be sure to include your email directories and photo libraries as well.
Also remember, making backup copies is great, but failing to make sure they work properly can cost you. Once in a while, take your archive media and try to access the files contained within it. Make sure that you can access and open your documents. Otherwise, you're still waiting on a disaster.
Good luck,
Perry