Go by the book

The most important thing in keeping a car performing properly is to follow the maintenance schedule in the vehicle owner's manual and make necessary repairs promptly. If you think you're saving money by skipping an oil change, think again. Missing even one oil change can accelerate premature engine wear and cause engine damage, reducing long term car reliability.

The manual contains a maintenance schedule that tells you how often to change fluids such as oil, transmission fluid, and antifreeze; when to rotate tires; and when to check and replace parts such as filters, belts, and hoses.

Maintenance intervals are increasing as new technologies extend the life of items such as spark plugs and motor oil. It isn't unheard of for modern cars to go 10,000 miles between oil changes and for spark plugs to last for 100,000 miles.

As long as you stick to the schedule, you'll save in the long run, even if some services are expensive. A pre-2006 Honda Pilot, for example, requires the first two changes of differential fluid every 15,000 miles and subsequent changes every 30,000 miles. The fluid costs about $30 a gallon, and with labor, the service can cost more than $100. But if you skipped enough fluid changes and the differential was damaged as a result, the repair could easily top $2,000.

When seeking long term car reliability, consider using what might be called the severe- or extreme-use maintenance schedule in your manual. Typically, drivers who need to follow such a schedule do a lot of city driving, live in a hot or cold climate or near the ocean, make a lot of short trips, tow a trailer, or drive in dusty conditions. If that sounds like it includes a lot of drivers, it does.

The difference between the regular maintenance and extreme-use schedule can be significant, with oil-change intervals as frequent as every 3,000 miles in the severe-use schedule, as opposed to the typical 7,500 in normal use. Intervals for other services also change accordingly under severe use.

Some vehicles have sensors that take the guesswork out of maintenance, and they can supersede the manual's recommendations. Some BMW, General Motors, Honda, and Mercedes-Benz models monitor the miles driven since the last service and record data such as how much stop-and-go driving is done, the engine temperature during each trip, and the time the engine spends operating at higher speeds. It then calculates how quickly your oil is breaking down and alerts you when service is due. Those systems can then adjust a car's complete service interval based on the severity of use and boost long term car reliability.

Overmaintaining your car is a waste of money. A common service scam to watch for is a dealership or repair shop that tries to add maintenance items that aren't specified in the owner's manual. That can add hundreds of dollars to a service visit.