I don't think I would touch them till needed. Then replace with grease able joints.
Scott-2013 F350 with a lot of tires.
2013 40' 4-slider stoneridge 5th wheel coming in at 15,400; 2015 Lincoln MKC
Previous Truck 2008 F250 6.4 with lots of upgrades and a suspension upgrade from Torklift International StableLoads