Pretty sure you know when you are putting your car through "hard use" besides tracking it. Other than that, 7500 is ok although I do my own oil changes once between 7500 if I have the time, if not, I just wait till the next one. Unless you are really pushing the car everytime you turn on the ignition, I really don't see a need for oil changes every 3000 miles. I just do it because I've too much time rotfl