@SZapper - That may be true. However, I know for a fact that a driveway edging is a must if you have a gravel driveway.
My grandparents had a gravel driveway at their house, with granite block edging. The edging was damaged one year, and a few of the blocks were missing.
Anyway, they were so overwhelmed at the time they neglected to repair that part of the driveway. After all, it was just a few blocks. How much could that really be protecting the driveway?
As it turned out, a lot! They had a bad storm, and a big part of their driveway was washed away. They had to pay the expense of repairing and re-graveling it themselves too!