The life of a spark plug really depends upon the type of plugs that are in your vehicle. Vehicles 15 years old or older are more likely to have standard plugs with approximate life expectancy of 20000 – 25000 kilometers. Newer vehicles up to model year 2000 are usually platinum-tipped, lasting approximately 50000 kilometers. Lastly, some 2001 and newer models come with iridium-tipped plugs which could last up to 150000 kilometers. Proper maintenance should be done on your vehicle so that it can run smootly without any hesitation.