You should change the oil at least as often as is recommended by the vehicle manufacturer (the information is in your owner’s manual). These days, that’s every 7,500 to 10,000 miles on many vehicles. Many mechanics recommend doing it more often, such as every 5,000 to 6,000 miles or every six months, whichever comes first. If you do mainly short trips and/or stop-and-go driving, you should change the oil more often. How about every 3,000 miles? Though that’s overkill, it can’t hurt, and it might extend the life of your engine.