I have a standard business liability insurance, costs me $400 per year. If someone does something stupid with one of my knives, or hurts someone with one of my fencing swords, or if I mess up someone's jewelry trying to fix it I'm covered. If you write a warrantee statement you can be held in court to all sorts of stupidity that could be inferred, derived or misinterpreted by anything you do not specifically rule out with disclaimers. If you do put a warrantee statement, limit your liability to repair or replacement of the knife at your discretion. If I did not have a limit of liability in my wedding photography contract I would have had to re-create an entire wedding I got sued by a bride about (including flying in and catering for several thousand guests) because I had a camera malfunction and lost ONE picture that was not even part of my contract. Fortunately I had learned from the example of one photographer in Hawaii who actually did have to re-create an entire wedding because he had not limited his liability and got sued by bridezilla
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