My John Deere D140 with the B&S 724cc V-Twin calls for 50 hour OCI. After four years, it has averaged 29 hours per year. For the sake of simplicity I just change both the oil and filter once per year. I used M1 10w-30 EP for the first four seasons, but will be changing to M1 10w-30 HM this Spring. Why? Because I have some. Enough said...