I worked at gas station as a teenager, even turned wrenches for awhile. We would see engines like this from time to time. I went to school with an engineer from Mobil. He changed his oil every 12 months or 12K miles whichever came first...Mobil 1 was just coming onto the market. There were all kinds of stories out there. You couldn't use in older engines because it was so thin it would cause leaks etc, etc, etc....well, fast forward to my days at trucking, and the police thing. We would send our oil out to have it analysed. They would always come back with very high oil change times. Unless you work the heck out of something, over heating, and such, like a farm tractor, heavy equipment, etc...most oil will never break down for 12-25K miles...but you do have to change it. I change mine every 7k, but I wouldn't think 12k is out of line. I do run mine hard from time to time, so I change a little early....oil is important, so don't skimp...and don't trust that crazy car to tell you, trust yourself...lol