Review on NGK 9198 CPR7EAIX-9 Iridium IX Spark Plug 4-Pack: High Performance and Durability by William Obong

I have been using Iridium spark plugs in my 1987 Honda Shadow for many years and have yet to replace the first set which keeps the spark plugs running smoothly, probably way longer than their normal lifespan. (and at 78,000+ miles it's still working fine.) I recently bought a new Yamaha Bolt and installed these iridium plugs, although I could probably use OEM iridium-free plugs for a few years. I just love the smooth engine response that iridium candles give the engine.