After years of working in the equipment industry and being a hot rod lover, I'm also on board with the 3 to 3.5 K mile or 100 hour program, My 77 chev, crew dually one ton has 682K plus almost 683K miles on her,,, and during an off the line foot race with a new mustang I finally popped something loose and have a very slight bottom end noise... keep in mind, this is an OLD one ton truck with a flat bed so she also happened to have 2 tons of hay on board. Which for the engine/tranny combo I run is not a big deal... and yes, it was dumb as heck, but I put my money where my mouth was and whipped the crap out of the mustang,,, (thank GOD the guy had no idea how to shift that new car or he wouldn't beat me royally) But it was worth it and I read my apponant right.... anyhow, my point is, MAINTENANCE< MAINTENANCE< MAINTENANCE!!! Maintenance is cheap, not many rigs can say they will see that many miles with out maintenance. Until the day I did that, this truck had never ever broke down on me or ever once left me questioning it's reliability. I've always been able to just hop in and go at the drop of a hat. And I don't know if there is a feeling so frustrating as getting in your vehicle or tractor and turning the key and not having it run right,, or die right in the middle of doing something, especially when you really need it.
House tractors like my shibaura 2643 should be done once a year or every 250,,,, I really don't use it much and maybe put 19 hours a year on her lately,,,, but tractors attract moisture. You have to get rid of it,,,,, and leaving old filters in just contaminates the new fluid.
Our big hay tractors,,, (I do all the maintenance for commercial hay growers, and every one has their own thing, But the one outfit that farms some of the roughest ground, and has the best reliabilty factors is the one that farms 800 acres here locally,
I change out his filters every 100 hours,, or about 5 to 12 times a summer (depending on the unit). His rigs work in heavy dust and dirt and get fuel that comes in from mobile and gravity feed shop tanks from the various locations he has hay feilds.
Plus, we never know what kind of stuff can be in the bottom of the tanks on the delivery trucks,,, So we don't just do oil and air,,,, fuel is also SUPER important and often the most neglected. When you figure the cost of a fuel pump or worn/clogged injectors, let me tell ya, fuel filters are dirt cheap.
Back when I had a commercial tractor repair shop, the two most common things we saw was neglect and overuse/ over loading on compacts causing 95% of all the failures. None of which end up cheap.
Just my two bits.
An ounce of prevention is worth a pound of the cure.
Paula