I have a BX1870 with about 120 hours on it. I have done all the required maint on it in the past. I use to mow grass with it but I now use a Toro SWX 5050. I occasionally use the BX with the FEL to move things around and I have the 5450 snow blower for it that I use in the winter. I only have been putting about 15 hours on it a year. My question is when should I change the oil. I have always changed oil on all my equipment yearly no matter how little use it gets. Just not sure about the diesel.