Sorry if this has been discussed before but getting ready to change plugs on my 500EFI motors and wondering if the AC MR43T plugs are still the recommended plug or
have they been surpassed by new technology like an iridium tipped plug? Also curious how often others are changing them. TIA

NGK BR6FS is used by Merc to replace the AC MR43T

I see no reason to use iridium or platinum spark plugs. Marine engines just don't get nearly the number of hours as cars do to necessitate them.