Both situations share one problem: keys exist that you cannot account for. A roommate who left angry may have handed a copy to someone. A previous owner has no idea how many keys were cut over the years they lived there. In neither case does the door being locked mean much.

What a lock change covers

A lock change puts new hardware on the door, and the old key stops working because the lock it belonged to is gone.

How much gets swapped depends on what is there. Where the existing lockset is sound and you want to keep the finish and handle style, changing the lock cylinder alone puts a new keyway on the door. Where the hardware is worn, damaged, or lower grade than an exterior door warrants, the full lockset comes off. An old door lock replacement is the point at which you can move up in security rating rather than replacing like for like.

A residential locksmith will confirm which applies after seeing what is on the door.

When a roommate moves out

Who is named on the paperwork decides what you can do.

If you own the home, the decision is yours. If you rent and the departing roommate is on the lease, changing locks on an apartment without the landlord’s involvement can breach both the lease and local tenancy law, even after the person has physically moved out. The reverse question comes up just as often: can a landlord change the locks on a tenant? In most jurisdictions, not without going through a legal process first.

Rules vary by province, state, and municipality. Check your lease and your local tenancy legislation before booking work, and expect any locksmith to ask for proof of ownership or written authority from the landlord.

When you move into a new home

Treat every key as unaccounted for on day one. Previous owners, their relatives, contractors, cleaners, agents, and the neighbour who watered the plants may all have copies, and none of that appears on the closing paperwork.

Changing locks on a new home is a first-week job, not a someday job.

Do not stop at the front door

A front door lock replacement handles the door people knock on. The gaps are usually elsewhere:

• Back and side entries, often fitted with older or lower grade hardware
• The interior door from an attached garage, which counts as an exterior door
• Patio door lock replacement, frequently overlooked because the door is glass
• The mailbox lock, which protects documents rather than the building

One key for every door

New cylinders across your exterior doors can be set to a single keyway, so one replacement house key opens every entry point. Setting that up while the hardware is being changed is simpler than matching it later. Kwikset and Schlage locksets are both commonly handled this way.

If any door carries a keypad or smart lock, the old user codes need clearing as well. Changing the hardware next to it does nothing about a code someone still remembers.

Need locks changed quickly? We provide residential locksmith services on site, from a single front door to every entry point on the property.