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.
:hmmmm: Just wondering if it is okay for me to use Ron95 for my engine. Because I read some post that say high compression engine need to use Ron97 (eg:Civic Type-R) Any ideas all sifus? Mine engine is stock standard...