I was shooting the very first CO National match when halfway through the match my red dot came flying off my CO gun. The screws were sheared off. Thankfully I had an identical backup. Another match with a different gun I had a fairly new trigger spring break. But again, fortunately I had a backup. And another match where during the match my red dot lost zero. Thankfully I had a backup. The instances have been rare over the years, but enough that if I'm going to take the time, effort, and expense to go to a match I definitely want a backup.