Do you back up your data religiously? I didn't either for a while, but losing everything on your computer is a powerful incentive to starting backup up your data on a regular basis.
It was in about 1982 that I learned the importance the hard way. My partners and I had computerized our chain of video stores with a Radio Shack PC we'd upgraded to a massive 64K of RAM and two 5.25 inch floppy disk drives. Then, advances in technology let us buy a massive four megabyte hard disk drive on which to store our data, one of the most valuable pieces of which was a custom-built point of purchase program. That hard drive alone cost us four grand (and was about the size of the entire PC I use today) and we were proud to the point of smugness about it.
