Most homes or offices have multiple door locks. You will save money with the Atlas Rekeying Kit if you re-key your door locks yourself. Calling a locksmith can be very expensive if you have a lot of locks that need re-keying. Locksmiths charge a separate fee to re-key each door lock, regardless if they come to your home or you bring it to their place of business. Don’t overpay for a service you can learn how to do yourself easily.