10,000 miles seems to be the average "long" duration OCI I see in the UOA section. Does anyone here regularly do 20,000 miles or more without an oil change? If so, what oil/vehicle? How does it look coming out? UOA report? Noticeable sludge/varnish? I'm wondering if there is a trend in what oil brands can regularly do 20k+. Let's see who wins!