In 1997, I was working for a department at Montclair State University. The woman in charge had a lot of large files, and a need to be portable, so she used Zip disks (this is before the days of USB flash drives). At one point, one disk stopped working, and she hadn't backed it up, and was very upset that her data was gone forever.
Except that it wasn't. Many people don't realize that just because you delete something doesn't mean it is gone forever. The malfunctioning disk was sent to data recovery specialists, who recovered about 99% of what was originally on the disk. I looked like a genius for knowing that this type of company existed.
Whether a disk fails, things CAN be recovered. The key is, how important is the data? There is usually a price associated with this.
Another thing - if you delete something from your hard drive, it's not gone. Going back to the Microsoft DOS days, there used to be ways to undelete files. When you delete a file, it's not shredded; the hard drive simply says "oh, okay, I can use that space to save stuff now" - which means the original file is still there, just not being recognized by your operating system.
The next step up is computer forensics. There are more advanced ways to pull information off of a hard drive, which means that if you plan on being investigated by the FBI, deleting is NOT enough.
Anyway, some students in our Cyber Security and Computer Forensics certificate decided to put the skills learned in to use and open up a data recovery consulting firm called Old Data Never Dies. I've had most of the students in at least one class, and it's great to see the growth they've all undergone since the "Introduction to Windows" class days to the point where they are now.
The company's Web site can be found below.