I've been up in the air about 6 mo versus 1 year OCI on my wife's '07 Acura. She puts so few miles on it that if we went by the computer it would be over a year between changes. Since next month would be the 6 month mark, I was wondering if doing an analysis would be worth doing to show which would work better? Right now I've got PU in it and have had 'dealer synthetic' in it about once a year since new up until I started doing it myself in May. She drives short trips (under 5 miles) about 2-3 times a week and about once a month we take it over 20 miles one way to the shopping area.