There are a few factors you left out. What oil are you running? What type of intake and filter do you have? If you are running good quality oil, and are running a good oiled foam filter or paper filter, you could probably run it a full year if its less then 30-40 hours. If you are running a crappy K&N throw it in the garage and get a good filter! lol It lets too much by and contaminates the oil. Anyways, if you doubt what I say, run your oil for 5 hours and send it off to have it analyzed at Blackstone Labs. They can tell you how much life was left. They will advise you then on how many hours to go before your next change.