My most valued thing will be my thorn resistant tubes on both my MTB and road bike. I hope I'm not jinxing myself, but I have never had a puncture or flat ever since I've installed them. The tubes have added some considerable weight to my bike but I thinks its worth it for the peace of mind of not worrying about flats anymore. I once pried out a shard of glass from my MTB. Sucker ripped throught the tire but the inner tube was barely scratched.