If You just got the keys to a house you bought.
Then Rekey every exterior door to one new key.
The seller, their agent and any tradesperson who held a copy are now locked out, and you carry a single key. Lock Rekeying

Locks for shops, offices and buildings: rekeying at turnover, commercial-grade hardware, exit devices, master key systems and access control.
Small businesses often run on one key that everyone has a copy of. It works until it does not. The commercial pages explain the steps up from that: rekeying to a known set, a master system, then keypads or cards when keys become more trouble than they are worth.
Commercial RekeyingA key turned up in the parking lot with the shop's name on its fob.
Master Key System DesignA new hire at the shop gets handed whatever spare key happens to be in the drawer, and it turns out to open the stockroom, the…
Access Control InstallationDeliveries arrive before anyone is scheduled to be there, which right now means either propping the loading dock open at dawn or…
Panic & Exit HardwareThe fire inspector's note is blunt: the banquet hall's second exit still turns on a deadbolt, and the crowd it is rated to hold…
Commercial-Grade Lock ReplacementA new tenant moved into the unit next door, and the property manager just found three different cylinders on three doors, none of…Tap a situation. The answer opens here.
If You just got the keys to a house you bought.
Then Rekey every exterior door to one new key.
The seller, their agent and any tradesperson who held a copy are now locked out, and you carry a single key. Lock Rekeying
If You are renting, and the landlord says the locks were never changed.
Then Ask the landlord to have the locks rekeyed.
Tenants generally need the owner's agreement, and most landlords are glad to do it when asked plainly.
If A tenant moved out and did not return every key.
Then Rekey before the next tenant arrives.
It keeps the same hardware and closes the gap before viewings start. Lock Rekeying
On-site assessment preferred · (226) 271-6061, open 24/7