I have had mine in for about 3 years and it still looks good with no rips or anything, i have magnacore 10mm.

 

The mag 10's are a damn good spark plug wire and will last a very long time if properly installed. Look for any burnt places on them and just keep em clean


later

 

If your not experiencing any break-up or related issues, and the boots and insulation look fine, leave them IMO.

 

since his question was answered...i have another

is the insulation in the middle of the spark plug wire really necessary? i have a set that has protective gauze-like materiel surrounded by electrical tape.

common sense tells me its just to protect it from the heat coming off the block. would it be unwise to remove it? i think it looks ugly

 

I dunno about you, but I can't really see my spark plug wires unless I bendover the engine bay and use a flashlight or something. Why bother on the looks of something you can't see?

 

You generally test spark plug wires by measuring resistance from one end to the other. If you are running stock/nGK wires, the specs are in the FSM. Otherwise, check with the manufacturer for specs.

My last set was slightly out of spec after a few years and the car felt OK.

 

i guess you have a valid point