You just moved into a new Chicago apartment, lost a key on the L, or had a tenant turn over a unit. The next question is always the same: do you rekey the locks or replace them? Picking rekey vs. replace locks is one of the most common decisions Chicago homeowners and renters face, and most people overspend because nobody explains the trade-offs.
This guide breaks down the difference between rekeying and replacing locks in plain English. You will learn how each one works, what each costs in Chicago, when each is the smarter choice, and what Illinois law says about lock changes for landlords and tenants. By the end, you will know exactly which option fits your situation.
What Is the Difference Between Rekeying and Replacing Locks?
Rekeying and replacing are two ways to control who has a working key to your door, but they touch the lock in very different ways. One reuses the hardware on your door. The other swaps it out completely. The right pick depends on your locks, your goals, and your budget.
How Rekeying Works
Rekeying changes the internal pins inside your lock cylinder so old keys no longer turn it. A licensed locksmith pulls the cylinder, replaces the pin stack, and cuts a brand-new key matched to the new pin pattern. The lock body, deadbolt, latch, and exterior trim all stay on your door.
Rekeying is fast (often 5 to 10 minutes per lock), affordable, and effective. As long as your existing hardware is in good condition, the lock works exactly the same after rekeying, just with a new key. You can also rekey multiple locks to match a single key, which is handy if your front door, back door, and garage all use different keys today.
How Lock Replacement Works
Lock replacement (sometimes called a lock change) removes your existing lock entirely and installs a new one. The deadbolt, knob, strike plate, and cylinder all come off. New hardware goes in. You get fresh keys cut for the new lock.
Replacement is the right move when your lock is damaged, outdated, low quality, or when you want to upgrade to high-security or smart hardware. It costs more than rekeying because you are paying for new parts, but you walk away with brand-new locks built for the next 10 to 20 years.
Rekey vs. Replace: Cost, Time, and Security Comparison
Most homeowners pick rekey vs. replace based on three things: how much it costs, how long it takes, and how much security they get. Here is how the two stack up in Chicago in 2026.
Cost Comparison
Rekeying is almost always cheaper than replacement when your existing locks are in good shape.
Standard residential rekey: $25 to $50 per cylinder, plus a service call.
High-security cylinder rekey (MUL-T-Lock, Medeco): $75 to $150 per cylinder.
Whole-home rekey (3 to 5 locks): $150 to $350 total.
Standard residential lock replacement: $85 to $200 per lock (parts plus labor).
High-security lock replacement: $250 to $500+ per lock.
Smart lock or keypad install: $200 to $450 per lock.
For a deeper breakdown, see our locksmith cost in Chicago pricing guide.
Time Comparison
Rekeying is faster than replacement on every lock. A locksmith can rekey three to five doors in under an hour. Replacing the same locks takes two to three times longer, especially if the new hardware does not match the old footprint or the door needs minor adjustments.
Security Comparison
A rekeyed lock is exactly as secure as it was the day it was installed. If you have a basic builder-grade Kwikset, rekeying gives you a basic builder-grade lock with a new key. If you want stronger security, replacement is the only path. Upgrading to a high-security deadbolt, anti-bump cylinder, or smart lock means new hardware on the door.
If your goal is to upgrade security, see our high-security lock installation page.
When to Rekey Your Locks
Rekeying is the best choice in most everyday situations where the locks themselves are fine and you only need to change who can use them.
The Best Times to Rekey
You just moved into a new home or condo. You have no idea who else has a copy of the keys: previous owners, contractors, real estate agents, neighbors. Rekeying is fast and inexpensive.
You lost a key. A rekey makes the missing key useless without buying new hardware.
A roommate, ex-partner, or housekeeper moved out. Cut everyone off from access in one quick visit.
Tenant turnover. Landlords can rekey between tenants for under $200 per unit instead of buying new locks every time.
You want all your doors on one key. A locksmith can rekey several locks to match a single new key.
For new movers, our residential locksmith services and rekeying service pages cover the full process.
When Rekeying Is Not Enough
Rekeying does not fix worn-out locks, broken hardware, or weak builder-grade deadbolts. If a lock sticks, wobbles, or feels loose, the answer is replacement, not rekey.
When to Replace Your Locks
Lock replacement is the right move when the hardware itself is the problem, or when you want a meaningful security upgrade.
The Best Times to Replace
Your locks are damaged. A bent deadbolt, broken latch, or cylinder a thief tried to drill is not a rekey job.
Your locks are old or worn. Builder-grade hardware from 15+ years ago is past its useful life.
You want a security upgrade. Moving from a basic deadbolt to MUL-T-Lock, Medeco, or another high-security cylinder requires new hardware.
You want a smart lock or keypad. Going keyless means swapping the lock entirely.
There was a break-in or attempted break-in. Replace any lock a burglar touched, even if it still functions.
Your front door does not have a deadbolt yet. Adding one is a full installation, not a rekey.
For Chicago apartment owners and condo boards thinking about upgrades, our keyless entry systems Chicago page covers smart and keypad options.
Combining Rekey and Replace
You do not have to pick one or the other for the entire home. Many Chicago homeowners replace a worn front-door deadbolt and rekey the back door and side door at the same visit. A licensed locksmith can mix both jobs and key everything to one key.
Chicago and Illinois Lock Change Considerations
Chicago has its own quirks: vintage hardware, multi-unit buildings, condo associations, and Illinois landlord-tenant law. All of these influence whether rekeying or replacement makes sense.
Vintage and Older Building Hardware
Many older Chicago homes still have mortise locks, vintage skeleton-key sets, or odd-sized cylinders. Some can be rekeyed. Others cannot, and replacement is the only option. A Certified Registered Locksmith can tell you on-site within minutes.
Landlord and Tenant Lock Changes in Illinois
Illinois law does not require landlords to change or rekey locks between tenants, but it is widely considered best practice and many Chicago lease agreements include it. Tenants generally cannot change locks without written landlord approval, and any new keys usually must be provided to the landlord. Always check your lease and the Chicago Residential Landlord and Tenant Ordinance (RLTO) before making changes. The Illinois Attorney General consumer resources page is a good starting point.
Condo and Multi-Unit Buildings
If you live in a Chicago condo or apartment building, your unit lock may need to match a master key system controlled by the building. Talk to your association before rekeying or replacing, and have your locksmith confirm whether your hardware is master-keyed. Our master key system services in Chicago page explains how these systems work.
For a broader resource on consumer rights and locksmith standards, see ALOA (Associated Locksmiths of America).
Common Questions About Rekey vs. Replace Locks (FAQ)
Q: Should I change locks or rekey when I move into a new home in Chicago? A: For most movers, rekeying is the smarter call. It is faster, cheaper, and makes every old key useless. If the existing locks are damaged, builder-grade, or you want a security upgrade, replacement is worth the extra cost.
Q: How much does it cost to rekey locks in Chicago? A: A standard residential rekey costs $25 to $50 per cylinder, plus a service call fee. Whole-home rekeys (3 to 5 locks keyed alike) typically run $150 to $350. High-security cylinders cost more.
Q: Can I rekey my own locks? A: Some Kwikset SmartKey locks have a homeowner rekey feature, but most locks need a licensed locksmith with the right pinning kit. DIY rekeying on standard hardware almost always damages the cylinder.
Q: Is rekeying as secure as replacing locks? A: Yes, as long as your existing locks are in good condition. The pins are new, the key is new, and old keys no longer work. Security upgrades (high-security or smart locks) require replacement.
Q: How long does it take to rekey or replace locks? A: A licensed locksmith can rekey one lock in 5 to 10 minutes and a whole home in under an hour. Lock replacement runs 15 to 30 minutes per lock, longer for new installations or smart hardware.
Conclusion
The rekey vs. replace locks decision usually comes down to three things: the condition of your hardware, your security goals, and your budget. Rekeying is faster and cheaper, and it solves most everyday situations like moving in, losing a key, or tenant turnover. Replacement is the right call when locks are damaged, outdated, or when you want a real security upgrade.
Three takeaways to remember:
Rekey when the hardware is fine and you just need to change who has a working key.
Replace when locks are damaged, worn, or you want high-security or smart hardware.
Mix and match. You can rekey some doors and replace others on the same service call.
Not sure which is right for your home? Call The Professional Locksmith at (312) 796-0901 for honest advice from a licensed Chicago locksmith. We have served Chicago since 2012 from two local shops, and we will tell you the truth about whether you need a rekey, a replacement, or both before any work starts.