There are several reasons why people want to rekey a lock. The most common reason is moving into a new apartment, the most important thing for people is to know that no one else has the key to the house except them. The second thing is the obsolescence of the lock system inside.
The pins and the springs inside after a certain period begin to wear out and this can cause the key not to turn the lock. Our recommendation is always to save the customer money and do a rekey a lock instead of replacing a lock. The re-key operation is replacing the entire lock system with pins and springs, matching a new key with a serial number and eliminating the old key until no one can use it. we also can do master key (one key control all the locks in the house). In some cases, we advise the customer to replace the entire lock if it is a very old lock.
A little note: to make master key all locks must to be same brand.