 it's definitely not going to hurt to change them just for age on the other hand i have spark plugs in a model t that were put in in 1975 that are still perfect there's no reason to change them i'm not going to the electrodes not burnt they're not fouled there's no reason to change them in fact i bought some new plugs put in there when i went through and just looked at the engine and painted everything and the new plugs didn't really work as well they just didn't seem right so i put the old plugs back in and they they're still in there so i got the spare set but