A tune-up (also known as a major service) is regular maintenance performed on an automobile, or more generally, any internal combustion engine. Most automobile manufacturers recommend a tune-up be performed at an interval of 30,000 miles (48,000 km) or two years, whichever comes first.

As with all preventive maintenance performed on an automobile, tune-ups can prevent myriad problems from occurring on a vehicle. The filters replaced can clog with use and prevent flow, starving the engine of fuel or air. Spark plugs have a recommended service lifetime of either 30,000 miles or, in the case of platinum or iridium plugs, 60,000 to 100,000 miles (96,000 to 160,000 km), and old spark plugs may cause engine misfire.

Source: Wikipedia