AMSOIL probably will provide better protection than the petroleum oil that your referring to,but basically all that the oil does in your engine is take a beating so you cant expect it to show the same kinda strength that it did 500mi and at 10,000mi, with that said, Oil analysis is the best way to truly see how your oil is holding up in your engine and best determine what your drain intervals should be. The cost of AMSOIL vs. the other guys may be higher but your annual savings are much greater, geneally rif you stay under 25,000 miles a year you and you are running a AMSOIL EaO oil filter you only need to change your oil once a year.