Stock spark plug longevity

[Stanged78]

How long before I should install new spark plugs? My 2001 GT has 62,000 miles on it, and the plugs have never been checked or replaced. The car seems to run just fine. I am a spirited driver, but I don't drag race the car or often take it over 4,000 rpm. I use regular (87 octane) gas as recommended, and the only mods I have are a K&N air filter and a Spintech catted x-pipe with a Spintech catback.

 

[ponysarepretty]

Apparently goverment mandates require them to last at least 60k for warranty, thats why they are platinum. I believe maintaince sechedule calls for a change every 60k when subject to heavy usage and evrey 100k under normal conditions.