Originally Posted By: heathenbrewing
Conventional spark plugs generally last one year. Platinum or iridium can last, depending on manufacturer specifications, up to seven years. Why anyone would consider leaving plugs in for 7 years is beyond me though. A brand new copper plug will outperform a 6 month old PL or IR plug.
Do you realize that you contradicted yourself in your statement?
A brand new standard plug will not outperform a 6 month old PL or IR plug. why? well, the gap erodes at least 7 times slower on an IR plug, IR plugs require less voltage to fire and have a more stable spark.
Now think about price. If I have a 4 cylinder engine and I use the 2 dollar standard plugs, then it will cost me 8 bucks a year for plugs, not bad per say.
On the other hand, IR plugs last at least 7 times longer than the standard plugs. So do the math, 7 years worth of standard plugs will cost me 56 bucks, but if I buy the IR plugs I end up paying 32 bucks(8 dollars a plug). That gives me 24 more dollars in my pocket and less labor (not that its strenuous work, but still...its less wear and tear on the engine's head).
Who knows? Every engine is unique. If standard plugs work for you, then by all means keep using them. I just presented my opinion and don't expect you agree.