I have a friend that works at a diesel engine plant and he is always chuckling at how little farmers use their tractors, he says most farmers are putting less than 500 hours a year on medium size tractors and less than 300-400 on high HP tractors....

Diesel fume is using them more than average with 9000 hours on a 7510 - because he sounds to have livestock, so that pushes the hours up way beyond the average row cropper.....

My friend constantly tells me about mining equipment that's used at max load for a high % of 2-3 shifts per day and 6000-8000 hours per year. They go for 10,000-20,000 hours between major overhauls, going on to over 100,000 hours, within hard working and abrasive conditions. 

So what he says is, the amount of hours put on a tractor is becoming less and less as equipment gets bigger, plus if most farmers only use a tractor for maybe 300-500 hours per year, they probably don't need the reliability or build quality compared to say mining equipment. They also study engine loads and if a tractor is used for 500 hours, it spends like 20% idling and less than 50% under heavy load (roading, turning etc).

Don't shoot the messenger and Happy New Year to everyone.