What rekeying actually does
Rekeying changes the internal pin configuration of a lock so that all previous keys stop working and a new key takes over. The lock body stays on your door. This is why it is a common choice right after a move or a lost key, when you cannot be sure who still has a copy.
Rekeying can also key several locks to work with one key, which is convenient for a home with multiple entry doors. Because you keep the existing hardware, it is generally the lower-cost option when those locks are still solid.
When replacing is the smarter spend
If a lock is sticking, worn, damaged, or simply old and low-grade, replacing it can be the better long-term value than repeatedly servicing something near the end of its life. Replacement is also the path when you want to upgrade to higher-security hardware or a smart lock.
Style and consistency matter too. Homeowners sometimes replace mismatched locks so every door uses the same quality hardware and, if desired, the same key. The cost is higher up front because you are buying the hardware itself.
The economics, in general terms
As a rough guide, rekeying is usually priced per lock or cylinder and tends to cost less than buying and installing new hardware, especially across several doors. Replacement adds the price of the lock plus installation, and higher-security or smart models cost more.
These are general patterns, not fixed prices, and they vary with the number of locks, brands, and complexity. The most reliable way to compare is to get a written estimate for both options and choose based on condition and goals.
