Are you a Microsoft Outlook user? If you are, do you back up your mail folders regularly, so that if your hard drive failed or became corrupted you would still be able to recreate your e-mail environment without losing much?
For several years I did not even know how or where Outlook stored my mail files and address book, or contacts as Outlook likes to call them. Once I had figured all of this out, I got to thinking and realized tht even though I was backing up My Documents to an external hard drive, I had not taken any steps to ever back up my e-mail. I asked around, on online forums and such, and found out that the nearly hidden, very hard to find, location of my e-mail could be changed. Changed, in fact, to a location such as a folder of any name I chose within the My Documents folder if that is what I wanted. It turns out that this is exactly what I wanted to do. With all of my e-mail stored within My Documents in a separate e-mail folder (I call it My Outlook Mail Folders), it would then be backed up on a regular basis whenever I backed up My Documents and all of its contents. This is such an easy thing to do that I recommend it for all Outlook users.
You can read about it here:
http://office.microsoft.com/en-us/outlook/HA011124801033.aspx