Most car owners are accustomed to changing their oil based on mileage, but the time factor is equally important. Oil additives lose their effectiveness after about five years in a sealed container, and this period drops to just one year once the container is opened. The average American drives 16,550 miles annually, requiring about three oil changes per year. Even if annual mileage is low, engine oil still degrades due to oxidation and moisture absorption; therefore, changing it every six to twelve months is recommended.
Barely drive your car? Here’s why you still need regular oil changes
