i have a probably a 20yo craftsman lt100 rider. bought it used 11 years ago so i really don't know how old it really is. 17hp 42" cut. i have never changed the plugs or the air filter. only the belts, blades, and battery. i just changed the oil last year for the first time. i don't winterize it, just park it for the winter and remove the battery. throw the battery in in spring and it's runs after a couple of turns of the motor.