cutting plugs

been reading my plug with a otoscope but see on the bullet most cut there plugs. and i only do one inner one corner. at the end of the track i pull the 2 plugs and replace them with new and drive back to the pits

I cut them also, untill tune up is close, then pull and look at them when i start bigger tune ups i pull all 8 and check. plugs are cheap, pistons not so much.