If there is a tube of cement with them....THAT is the weak link. The plugs should be good ad infinitum as long as they do not dry rot.
Check on your glue... it both the SEALANT and the LUBRICANT to get the plug through the puncture.
"For Gawd's sake, put a RELAY in there or you could burn the whole damn Jeep to the ground" ...this quote brought to you by people who do not understand the law.....Kirchoff's, Ohm's, or Faraday's.
Violation of KISS shall always ring false in TRUE engineering. - ME___
Had 75CJ5, 89YJ, 93YJ. Have 82CJ7 & 95YJ____Not one burnt yet due to lack of relays.