I had one of my drivers asking me:"When do I need to change plugs?" at 178k on his Lincoln Town Car. They looked bad when we pulled them, but the car ran like new. The same driver asked about his belt at 209k. Boy, I never saw a belt like that. He is the owner, great customer service skills, but needs help with some maintenance items. I don't know what we are going to do when we run out of LTCs. They are not being made any more.
Double plats are good, regular plats may be a gimmick for DIS cars like ours. Iridiums are proven champions in longevity.