The recommended frequency for changing vehicle oil varies depending on the type of oil used, the car manufacturer’s guidelines, and driving conditions. Modern cars using synthetic or semi-synthetic oils typically require oil changes every 7,500 to 10,000 miles or about every six to twelve months. Conventional oils usually need to be changed more often, around every 3,000 to 5,000 miles. Some newer cars have oil-life monitoring systems that alert drivers when it’s time to change the oil, adjusting for actual driving conditions. Severe driving conditions, such as stop-and-go traffic, frequent short trips, towing heavy loads, or driving in dusty environments, may require more frequent oil changes, possibly as often as every 3,000 to 6,500 miles. Cars that are not driven often should have oil changed at least once a year to prevent oil degradation. Ultimately, it is best to follow the car manufacturer’s recommended oil change interval stated in the owner’s manual, as well as any oil-life monitoring system prompts, to maintain engine health and warranty coverage.