Changed my OEM shocks about 4 months after my ordered new Duramx CC LB 4X4 truck came in because we carry a very heavy 11'4" Lance TC or our Carriage Carrilite 5th wheel with the truck and all it's ever used for. Carriage Carrilite's are not at all light in weight! Ours scale weighed 12,840 loaded to go down to Florida. I went with Rancho 9000X adjustables and they have been excellent and am very pleased. Now have 155,677 miles on them as of today and still working great. Was going to go with Bilstiens but too many RV towing people/friends we know had said they were not happy with or very displeased with theirs. The Rancho's being adjustable is great and allows the truck to ride so much better when unhitched like when in Florida for our 2 to 2-1/2 months in mid January till about the end of March. If they ever wear out or fail, a new set of the Rancho's is all that will be on our truck.