I got an NGK Iridium and thought I would give it a try. When I removed my old plug I was surprised by the condition it was in. Other than a little carbon build up on the ground electrode it looked perfect - even had the original .024 gap after 4500 miles. I had one of those "if it ain't broke" moments and was almost afraid to change plugs since my bike was running perfectly. Put the new NGK in anyway and the bikes still runs great and now I have an extra plug. Apparently the TW is not very hard on plugs(or anything else).
2017 TW200, 2012 Ducati Multistrada, 2006 Polaris Hawkeye