Start with your owner's manual
Automakers set oil change intervals based on engine design and the oil the engine needs. The manual lists the recommended interval and the correct oil grade, such as 5W-30. Follow those details rather than a rule of thumb from years ago.
Many newer cars also have an oil life monitor that estimates when a change is due based on how the engine has been run. If your car has one, it is a reliable guide.
Conventional, blend, or full synthetic
Full synthetic oil generally resists breakdown longer than conventional oil, so it often allows longer intervals. Some engines require synthetic, so check your manual before choosing.
Whatever oil you use, the interval in the manual for that oil type is the one to follow.
When to change it sooner
Manuals often list a severe service schedule. It applies to frequent short trips, stop-and-go traffic, towing, dusty roads, and very hot or very cold weather. Many drivers fall into this group without realizing it.
If you fit that description, plan on changing oil more often than the standard interval.
Check the level between changes
Check your oil with the dipstick every month or so, with the engine off and the car on level ground. Some engines use a bit of oil between changes, and running low can cause serious damage. If the oil warning light comes on, stop driving as soon as it is safe and have it checked.
