What axle sliders do, despite the name, is actually protect the ends of your forks. Forks can be a real pain financially to replace, and often times fork damage can be the difference between insurance repairing your bike and totalling your bike.
For example: When my Vstrom was backed into by a Fertilizer truck one of the forks was damaged. it wasn't even bent. The shop said both forks were still true. It was just cosmetic damage, but it would have required the insurance company to replace the lower fork tube. They specifically cited this as one of the expenses that rendered the bike a "total loss" rather than repairable. That and the dent in the gas tank. That wasn't a sliding accident, but i told the story to illustrate just how expensive those parts can be and how it can tip the repair bill over the line. If you're in a slide and you have a good set of axle sliders, you'll avoid damage to your forks 9/10 times. engine guards will do the same for the engine and the front end of the bike. If you add Bar-end sliders to the engine guards you can usually even avoid damage to your gas tank. This really helps keep the bike from getting totalled in the event of an accident.
I think about these things a lot because I want to keep my CB1100 no matter what, and I can't have some insurance company declaring it dead on arrival just because i took it for a little slide.
