I think the initial change of fluids would be advisable to clear up all the cuttings and debrie in the transmission and engine. After that I would say change every couple of years. I think more than that you're wasting money. About the only consideration would be if it were left out where moisture droplets would be created by excessive sunlight. Modern oil especially synthetics can go a lot of mileage and hrs. Just changed out mine in Camry after 10,000 miles.

I went with Shell Rotella Diesel for my tractors....I don't know who Deere's source of oil is, but it's rebranded. My tractors...one with 1500 hrs and the 785 hr. tractor does not loose any oil....I've always been extremely impressed by the operation and balance of the 3 cylinder Yanmar sourced engines...have had some 4's but they weren't as smooth as the 3 due to firing degrees. Seems like the 180 degree firing has always been the smoothest. Also I check and blow out the air filters every change. A good source of oil standards and other materials used in engines is the Utube " project farm'. this poster trys all the brands and methods out in real time on machinery...light engines preferrably....one other somewhat waist is the excessive use of additivies. But to each his own.

Excuse my math....meanth the 240 degree firing....