a standard spark plug should last 10-20K KM...those better/performance type should last 30-50KM....
Spark plug is wear and tear part...
Also life span of spark plug depend on your engine condition...if your engine makan engine oil / wrong tuning then your spark plug will wear out faster.
The teams still battling it out on track are at the halfway mark as the 2010 Merdeka Millennium Endurance Race enters its sixth hour with things sailing smoothly so...