In a car that has Oil Monitor, using full syn, the day it complets one year the oil will be automaticaly FUBARded (?!) ... If I don't do many cold starts, short trips or idling and the oil has say, less than 7-8k 50%+highway miles I'd go by the 10k mileage beyond the 1 year mark, if out of warranty of course. But that's just me.