Start with the condition of your lock and the reason for changing it. A different key may be all you need, or the hardware itself may need attention.
When rekeying may suit
A compatible lock in good working condition can often be rekeyed. The internal keying changes, so old keys no longer operate that lock. It is an option to discuss after moving or losing a key.
When replacement may suit
Replacement may make sense for damaged or worn hardware, a lock that cannot be rekeyed, or a change in the way the entrance is used. A different lock is not automatically more secure: hardware selection, the door, frame and installation all matter.
Before choosing
Ask about compatibility, the condition of the existing hardware, the work involved and the total price for each suitable option.