The parts a locksmith needs to rekey a high security lock are typically pretty cheap and for this reason, it is almost always cheaper to rekey high security locks rather than getting them changed. When you have locks changed, you will be charged for labor and parts, but when you take advantage of rekeying services, a locksmith is only charging for labor. However, if you don’t have the matching key to the high security lock, and a locksmith must pick it, this additional charge can make rekeying more expensive than replacing your lock.