For what it's worth I do hydro oil and filter changes at 200 hours or 2 years, never had one go to 200 hours, more like 100. Back when I was a kid my uncle who was in charge of the maintenance of the company equipment told me that oil and filters are cheap compared to the parts you will replace if you don't take care of it and you'll change the oil and filter when you rebuild it anyway. Figured he was older and smarter than I was so I listened. Do as you please it's your equipment and your $$$$. Rant over. Return to regular programing.
