I've been riding bikes since I was around 5, I have never had a chain break yet. If I ever experienc my first chain break and don't have a tool I'll have to deal with it. I don't normally ride very far from an easy call or ride to get home. If I decide to ride somewhere there is not an easy call or ride home I may decide to carry a chain tool and some links. I carry what I need to fix a flat if I have one.