1 year. How long this lock installed by the carpenter lasted. Thankfully no one was stuck inside. Why use a locksmith? Because we know how locks work, and how they break. The $5 that the chippy/handyman saved has ended up costing a lot more for the customer. Don't risk an unlicensed operator. Use a qualified locksmith.
...Update. Another failure on Sunday with the exact same brand of lock, and the exact same problem. Oh well! It keeps me busy.