This is going to get interesting, I think. Our area's premiere auto repair facility, no longer believes in, or promotes, or will do, frequent (3000-5000) mile oil changes. They are advising their customers to go up to, or beyond 15,000 miles. They only change the filters now.They say they have the latest technical data and it shows that the longer the oil stays in your engine, the better it is for it. Again, this is not a fly-by-night shop, rather one that has been here many, many years, with highly trained techs, that command VERY premium prices for their services.. So what's your opinions?