I a little bit of a different application, I just drained the oil out of the Wife's Kawasaki Versys 300X motorcycle. She only rides it about 500 miles a year. Three years ago, I changed the oil and filter, pouring back in Rotella T6 15w40. This spring, a week ago, I dumped the oil and it was golden new, I unscrewed the filter and dumped out the oil and screwed the filter back on and filled the sump back up with T6 15w40. I figure the filter can go another two years for five years total.... Its a Bosch.