This one has over 4000 engine hours but the front tracks were moved to the rear and vice versa at about 3500 engine hours. It’s ballasted very heavy so there isn’t much wear on the tread at all. You loosen the tracks and remove the outer idlers at each end and take the track off the undercarriage. Stubble wear at the intersection of the lugs on the front tracks creates a crevice in the rubber. The front ones also operate in much more heat and radiation from the engine.
On this particular one, I think that rotation was done a little ahead of the tracks actual half life. I wasn’t there, but I think they used a tech, two helpers, jacks and blocks and a loader with a fork attachment, I don’t know how much time.