The short answer
A smart lock lets you assign a separate code, sometimes scheduled or expiring, to each person who needs entry, and its access log records when each code was used. The log is only as useful as the codes behind it: if everyone shares one generic code, it can only tell you the door opened, not who opened it. The most common gap is not the code system itself, but forgetting to delete a code once it is no longer needed.
A house-sitter's stay ending or a contractor's job finishing are the two moments this most often gets missed.
Unique codes vs one shared code: why it matters for the log
The single decision that determines whether a smart lock's access log means anything is whether each person who needs entry has their own code, or whether the household is using one shared "family code" for convenience. With a unique code per person, the log can tell you who used the door and roughly when. With one shared code, the log can only tell you that the door opened, which is barely more information than a mechanical lock would have given you.
This is not a minor style choice. It is the single most common real-world mistake in how households actually use this feature, and it defeats the entire point of having a log in the first place. Setting up unique codes takes a few extra minutes during installation, and that time is what actually makes the accountability feature real rather than decorative.
What an access log actually shows you, and what it doesn't
An access log is a convenience and accountability feature, not proof of who was physically at the door. It records that a specific code was entered at a specific time, assuming each code is tied to one named person. It does not confirm identity the way a photograph or a witness would; it confirms that whoever knew or held that code used it. If a code has ever been shared informally, borrowed, or written down somewhere visible, the log's connection between "code used" and "specific person present" gets weaker.
Any claim about exactly how many codes a specific lock model can store, or how long a specific manufacturer retains log history, depends on that model and has not been independently verified for this general guide, so this piece describes the mechanism rather than a number: locks in this category typically support multiple simultaneous codes and keep some history of use, and the specifics are worth checking in your own lock's documentation.
Scheduled and expiring codes for short-term guests
Beyond a simple, permanent code, many smart locks in this category also support scheduled or time-limited codes: a code that only works during a defined window, such as a cleaner's regular hours, or a code that expires automatically after a set date, such as a house-sitter's stay. These are worth using deliberately rather than defaulting to a permanent code for every guest, since a scheduled or expiring code removes the second half of the risk covered in the next section, the code lingering in the system after it is no longer needed, without requiring you to remember to go back and delete it manually.
Not every code type is available on every lock, and the exact scheduling options vary by model, so it is worth confirming what your specific lock supports rather than assuming every model offers the same flexibility.
The habit that undoes all of this: not deleting old codes
The most common real-world security gap with smart lock guest codes is not the code system itself; it is a code that was never removed after it stopped being needed. A house-sitter's stay ends, a contractor finishes the job, a former roommate moves out, and the code they were given quietly keeps working because nobody went back into the app to delete it. Unlike a physical key, which someone has to physically hand back or have re-cut against, a digital code that is never deleted simply continues to function indefinitely with no visible reminder that it is still active.
Building a habit around this closes most of the real gap: whenever a temporary guest, service provider, or short-term occupant's need for access ends, treat deleting their code as the last step of the interaction, not an optional cleanup task for later. Periodically reviewing the full list of active codes in the app, even for codes assigned to household members, is worth doing occasionally simply to confirm nothing forgotten is still sitting there active.
What a code is not: it's still not the same as watching the door
A code system and its log are a convenience and accountability layer, not a security guarantee, and it is worth being direct about that rather than implying more certainty than the system actually provides. A code tells you what was entered and when, assuming good hygiene around unique codes and prompt deletion; it does not tell you who was physically present the way a camera would, and it cannot stop someone who has learned or guessed a code from using it. This site's guide to indoor cameras and household privacy covers the parallel household-access conversation for cameras, which is a different and more sensitive layer than a code system, worth thinking through separately rather than assuming a lock's log covers the same ground a camera would.
For the physical security side of the lock itself, separate from who has a code, this site's comparison of a smart lock against a traditional deadbolt is the relevant read. And this site's guide to what happens when a smart lock's battery dies covers the other practical ownership question every ambient smart lock user eventually runs into. If Wi-Fi connectivity for these features is a concern, do smart locks work without Wi-Fi is the lock family's hub page on that question. And for anyone still deciding whether a smart lock fits into a broader setup, building a smart home security system with no monthly fee covers the buying order.
FAQ
Do I need a separate code for every person who uses my smart lock? For the access log to mean anything, yes. A shared generic code lets the lock open normally, but the log can then only tell you the door opened, not who opened it, which removes most of the point of having a log.
How many guest codes can a smart lock store? This varies by model and is not something this general guide states as a fixed number. Check your specific lock's documentation for its actual code capacity.
What is the most common mistake people make with guest codes? Forgetting to delete a code once it is no longer needed, such as after a house-sitter's stay ends or a contractor's job is finished. The code keeps working silently until someone removes it.
Can a smart lock give a guest a code that expires automatically? Many models support scheduled or expiring codes for exactly this reason, so a temporary guest's access ends automatically rather than depending on someone remembering to delete it manually. Availability varies by lock.
Is an access log the same as knowing exactly who was at the door? No. It is a convenience and accountability feature that records which code was used and when, assuming each code is tied to one person and hygiene is good. It is not proof of physical presence the way a camera or a witness would be.
I’m John Smith, the founder of Homegadgetguru.com. I use my IT background to extensively test home automation setups in my own house, giving you the hands-on, practical advice you need to build a smarter, more connected home.
