A lot of people ignore the manufacturer's recommendations, especially on automobiles. They go with what the dealer suggests, instead of what the manufacturer's suggest.
Worse than that, are the people that go with the "Quick Change type of people" that are making money from your oil change frequency. Why would anyone change the oil in a car every 3k miles, when the manufacturer says do it every 7500 (check your owner's manual)?
My wife used to change the oil every 3K and if they suggested an air/pcv valve, or anything else, she would go along with them. I cleaned out her glovebox and started showing how often they were charging her for certain items, that required the frequency of a lot less. Bless her heart, she doesn't think that people would actually take advantage of her!
As far as my tractor, I check the oil before each day's use, and watch to see what condition it is in. As soon as it starts showing some dirt, I either change the filter and drop another quart in it if I am pushed for time, or I go ahead and change all the filters, and the oil at the same time. I try to change all of them at once, so I don't have to keep track of what needs changing when...
I realize changing the oil too frequently isn't what you had in mind, and a lot of people will argue that it is good for the tractor, but why throw good money down the drain, and waste our natural resources, and feed the people that are using oil money to fight us? With double or triple costs in oil changes over the life of the tractor, you might come close to buying a new tractor, if the money were properly invested.
David from jax