Originally Posted by JimBlake
Seems like you'd have to support that with oil analysis. I don't see a lot of people on BITOG saying to go long intervals without UOA.
Degradation of the oil itself isn't the only thing to worry about. There's dilution with fuel, contimination with combustion products, all sorts of other things can happen beyond the control of the actual oil.
If you search around, you'll see tons of oil analysis for Mobile 1. I'm not sure about the new 15k stuff, but "regular' Mobile 1 synthetic has been around forever. I've known of people using it way back in the day. They recommend 12 months or 12,000 miles I believe it is for Mobile 1, whichever comes first. I personally have been using Mobile 1 for a while now, but I change it every 6 months or 6,000 miles, whichever comes first. In the end, I change the oil half as much as regular 3,000 mile oil and the cost comes out to be roughly the same.