Iridium, platinum, they all last much longer than the conventional copper plugs. As I remember, the copper plug replacement interval was about 60,000 miles, while the iridium and platinum plugs last 100,000 miles or more. Check your owner’s manual. I am quite sure it recommends iridium or platinum. I would be very surprised if the original iridium or platinum plugs need to be changed at 60,000. You could use the conventional copper plugs, but considering the longer service life, iridium or platinum plugs are not more expensive than copper plugs.