Rekeying vs. Master Key: Which Is Right for Your Building?

Rekeying is the right call when you need a one-time reset — a new tenant moving in, a lost key, a security concern — on a single unit or a small number of doors. A master key system is the right call when you're managing ongoing access across many units or doors and need a structured hierarchy (superintendent, manager, individual tenants) that doesn't require touching every lock every time someone's access changes.

What Rekeying Actually Does

Rekeying changes the internal pin configuration of an existing lock cylinder so old keys no longer work, without replacing the lock hardware itself. It's the standard response to:

• Tenant turnover — resetting a unit between occupants.
• A lost or stolen key — closing the security gap without waiting for a full lock replacement.
• Employee departure — for a business with shared physical keys rather than individual credentials.

Rekeying is fast (often 15–30 minutes per lock) and inexpensive per door, but it's a one-at-a-time operation — rekeying doesn't inherently create or maintain a hierarchy across multiple units.

What a Master Key System Does Differently

A master key system is a designed hierarchy from the start: individual tenant keys that open only their own unit, submaster keys that open a group of units (a floor, a wing), and a grand master that opens everything. See our grand master key hierarchy guide for how multi-level hierarchies are structured on larger portfolios.

The tradeoff: setting up a master key system requires specially cut cylinders designed for the hierarchy from the start (or a professional re-pinning of existing cylinders to fit the new hierarchy) — it's more work upfront than simple rekeying, but it means staff access can be added or restructured without touching every individual tenant's lock.

Side-by-Side Comparison

| | Rekeying | Master Key System | |---|---|---| | Best for | Single-unit turnover, lost key | Multi-unit hierarchy across a building | | Setup complexity | Low — one lock at a time | Higher — requires planned key hierarchy | | Cost per event | Low ($15–$50 per cylinder typically) | Higher upfront, lower ongoing per-change cost | | Maintains hierarchy? | No — resets one lock in isolation | Yes — by design | | Good fit for | Landlords with a handful of units | Property managers, co-op/condo boards, larger portfolios |

They're Not Mutually Exclusive

Most property managers use both: a master key hierarchy for day-to-day building access, with individual unit cylinders rekeyed between tenants as part of standard turnover — without needing to rebuild the entire hierarchy every time. See our master key systems guide and property management security guide for how this plays out in practice.

Getting Started

If you're managing turnover on a handful of units, contact our team for rekeying service. If you're planning a hierarchy across a larger building or portfolio, our nationwide partner network can design and install a full master key system — request a quote to get started.