mattrparks
Member
I just changed my plugs, around 15.5k miles (5 years). Was having no problems but wanted to do a tune-up before taking it to the track next month. The plugs looked good, but you could definitely tell there was wear on the electrodes; if you looked square on the tip of the electrode, it was actually oval shaped and not round where the two arc paths from the sides had worn away some material. I don't know if it was really enough to make much of a difference on the gap; I didn't have any problems before and didn't notice any improvement after.