Since I don't put enough hours on my tractor(5403) to change oil by hours, (about 50 hrs/year) I do it annually. The tractor is used almost none from October to April. Seeing some posts concerning how diesel combustion affects engine oil, I am wondering if it would be better to change oil in October so the tractor sits all winter with fresh oil in the engine, or change it in April before using it. So, is it better to sit through the winter with the used oil or with fresh oil....or am I overthinking this and it doesn't matter enough one way or the other? Thanks.