If someone breaks my blade in a bout or a lesson, who should pay for it?

Usually you do, because blades are consumables and a break during normal fencing is treated as ordinary wear, not damage someone owes you for. That goes for a hard parry, a beat, a touch that lands at a strange angle, or your coach taking your blade in a lesson. Nobody pays for the other fencer's blade when one snaps in a bout, and coaches do not charge students when their own lesson blades break, which happens to them a lot.

The reason is metal fatigue. Every hit that bends a blade adds a little damage, and a blade that has been flexed thousands of times eventually fails on an action that looks routine. The bout or lesson where it snaps is usually just the last straw. A blade that keeps taking a set after ordinary touches, or holds a bend in the same spot, is close to the end. There is a safety upside too: a blade that breaks in someone's hands or on a slow action is one that did not break in the middle of a lunge at an opponent.

It is reasonable to ask in a few cases. If someone handles your weapon without asking, such as bending it to straighten it, and it snaps in their hands, a polite conversation is fair, and plenty of coaches simply replace it. If you lend a weapon and it comes back broken, the borrower usually offers. If a new blade breaks within days, talk to the seller about a defect. And if someone was being careless or angry with your weapon, stepping on it or throwing it, that is no longer normal wear. Ask calmly and be open to splitting the cost or a discount rather than demanding a full replacement.

To avoid the argument altogether, ask before you touch anyone else's weapon, and if you offer to straighten one, say up front that old blades sometimes snap. Learn to straighten your own by bending it gently, never on the strip during competition, where that is a penalty. Retire tired blades to drills, and keep a spare so one break does not end your practice. When your blade does go, treat it like worn out shoes: replace it and move on.