I use a dental 10X magnifeyer to look at my plugs closely,, I do replace them when the center ground electrode gets rounded off from wear or it is wearing on a angle to the ground strap shruggy
I do see what looks like slag or metal hanging off to one side of the center electrode also when the motor is to lean making the plugs do that shock down
Get a good magnifer to help you get a good close look at your plugs and then decide scope

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)