My friend has a GPS device in her car from the insurance company to track her driving patterns to lower her premiums because she drives so little. One of the benefits of this is that she can log into their website and see every trip made including how much time was spent idling, max speed & overall driving time. She makes frequent short trips daily, averaging 7.3 trips per day over a span of 1.7hrs driving time per day, this month. While 1.7hrs of driving a day seems like a lot, she only covers 53KM (33miles) on average per day. It's probably close to an hour of idling daily, mostly from picking up/dropping off kids, getting groceries, shopping etc. I believe that this is the most extreme usage pattern I've seen for engine oil. Frequent short trips + traffic jams when the engine does warm up. The car is a Lexus ES330 with the 3MZ-FE V6 that seems to run fine. I was thinking that with this usage pattern, OCI should be based on hours of engine run time instead of mileage. Any ideas on what a good estimate would be? BTW the car does NOT have an oil life indicator, it was only available in American models, Canadians didn't get it. It is running 5w20 PP right now and will be hitting ~4K miles with ~220hrs of engine run time by the end of the year. I'm thinking that'll be a good time to change because I've read about heavy duty diesel applications that recommend changing oil after 200hrs. Thanks in advance.