Heck, the manual that comes with the car recommends that the oil & filter are changed every 7K. If the book says 7K why all the discussion?
Book say 7K, 7K it is!
If anyone wants to spend the extra bucks & change the oil more frequently, so be it. It's just a waste of oil, IMHO!
I've always thought that the 3K oil change interval has been over-marketed by the oil companies anyway. My Cougar manual says to change the oil every 5K, filter every other oil change.
Unless I'm driving the car through the desert every day or driving it in less than stellar conditions frequently I'll stick to what the manual says !