Mr Ron,
My machine has been going for more than 4 years now and still no wear to the Ertalyte wheels. If you use the right plastic it will not wear on a steel rail and with bearings mounted inside it is impossible to stick.

The machine was converted to a plasma cutter about two years ago. It cuts every day and the rails are not cleaned on a regular basis. One would expect these conditions to worsen the case but, not so.