One point about frequency of oil changes mentioned above, by not changing your oil at the car manufacturers suggested interval you run the risk of voiding the warranty on the car (if you have warranty remaining). I know you feel Exxon/Mobil will warranty you in this case but I am sure they have some small print in their warranty that exonerates them.
Believe what you want to believe. Again, like I said before, manufacturers make you change the oil more necessary than needed so they can make more money off of you.
Most cars can be changed at 5k miles on Dino Oil (even in the owners' manual) ,so synthetic oil can be changed much longer than that. If you look at the used oil analysis on the Mobil 1 EP on people who actually have driven their cars 15k miles, it's so far been great. The average car manufacturer recommends changing oil every 7.8k miles, and this isn't even on synthetic oil.
It's fine if you want to waste your money. Do what makes you happy. Your car's engine will probably outlast far more than other components before you decide to trade it in or junk it.
As for voiding the manufacturer's warranty, the warranty usually only last until 40k miles anyways, so that is a moot point. Your engine even if you don't change the oil will outlast after the warranty expires. On the Infiniti vehicles, they last until 70k miles, but I have gone past that anyways.
Last edited by mathnerd88; 12-03-2012 at 11:37 AM..