How often should you change your car's engine oil?

For most modern cars, engine oil should be changed every 5,000 to 7,500 miles if you use conventional oil, or every 10,000 to 15,000 miles if you use full synthetic oil. The old standard of every 3,000 miles is largely outdated for modern vehicles. The best approach is to follow your specific vehicle manufacturer's recommendation, which you can find in your owner's manual. Some newer cars have oil life monitoring systems that alert you when a change is needed based on your actual driving conditions. Factors like frequent short trips, towing, or driving in extreme temperatures can mean you need changes more often than the standard interval.