The purpose of the Tune-up Kit is to provide the common Preventative Maintenance parts that are designed to wear over time and be replaced, such as the spark plug, air filter, and oil filter. These parts trap dirt and debris to keep it from damaging the engine. Very popular for homeowners, tune-up kits are not usually offered for the high HP engines found on larger commercial equipment. Most homeowners perform a tune-up at least once a year to keep their equipment operating at optimal performance.