I have 2 tractors 2007 and newer, with 3 between the ages of 1963-'88, all diesels. The old ones get WW HD 15w-40 C rated dino and the newer ones Rotella T6 5w-40 full syn. Since I'm retired and am currently a STO (small time operator) the once per year fits my needs. When I was a teenager, I just loved to change my oil....now it's a necessary PIA. On the rest of the fluids I try to change them out ever so often...like this year I was reading about changing fuel filters and realized that the 2007 was still the OEM filter. Got a set of filters and they all got changed.
On following what's recommended in printed literature, a little common sense goes a long way in saving you effort and your wallet: Printed literature is for the World; any body running the equipment, anywhere in the world, under any kind of condition. My 2 newer tractors are Bransons and are Korean made and after seeing pictures of Bransons working in Korean rice fields, no way does my equipment see that kind of abuse. Also, I can see why Branson sales literature show the tractors with R1 "Rice" tires......down here in Tx. they used to use steel wheels observed when I used to Goose hunt the coastal plains in the 50's.