Something isn't right, I have a pair that I moved fromOn the weekend I had the skid pulled out on my new to me Renegade to install the above mentioned MS bushings. The PO rode about 4-6000 Kms a season and told me the sliders should be replaced as he did them 2 seasons ago. I wrestled with the Duponts vs standard ones for a while and determined that my cash is better spent on other parts (MS bushings all around) and so I bought some standard ones to install.
I found that there was Duponts on it, and they were pretty well worn, so 8-10000 kms (5-6000ish miles). I've seen the standard ones last almost that long.
One sled to another that has almost 20,000 miles now that guess are worn 5-10%. Have two others 10-12,000 miles that could pass as new.