My mechanic just told me today not to obsess about all the hype around platinum and iridium plugs. Not worth it, in his opinion. Stick with standard copper plugs and change 'em on time. Nothing beats them for conductivity and in any case the other options are grossly overpriced. And why do you want your plugs to last your lifetime anyway? I found this article online that agrees with him. Inaonekana hii watu ya marketing nadangaya sisi...