When our son lost his wallet, which contained the key to the house as well, I happened to be driving by a Home Depot in Ajax, ON. I went in with the idea of purchasing 3 deadbolt locks to replace the front door, garage side door and through door from garage into house, as the lost key opened all 3 of those locks. The associate I found in the door lock area was soo helpful, he suggested I only needed to change the mechanism inside the lock, not the entire lock itself. I changed the 3 mechanisms for roughly $15.00 plus the cost of making copies of keys for the entire family. I went into the store believing I was going to plunk down at least $100 for new locks and came out only a few dollars poorer and with knowledge for future lock changes.