TUNE - UP
A tune up consist of spark plugs, fuel filter (if serviced able), air filter, ignition wires or boots. On older engines there maybe a distributor cap and rotor. The engine has to be mechanically sound for a tune up to be worth doing. The battery and alternator need to be good too.
A tune up needs to be done about every 30,000 - 60,000 miles depending on the type of spark plugs installed before. Most of the newer vehicles 2001 and newer can go 100,000 before they need new spark plug, but in some engines leaving them in that long could make it difficult to remove them and in some applications the plug will break off in the cylinder head and require special procedures to remove the spark plug from the engine, this will increase the cost of the service significantly.
A tune up is absolutely necessary to do to keep the engine proforming at peak performance. Neglecting to have a experenced technician inspect the engine for need for a tune up can lead to the engine stalling at stops, hard starting , rough running, increased fuel consumption and warning lights coming on that will increase the overall cost to diagnose why the light is on and possible damage to the exhaust system.