A smart lock is one of the few smart home devices that can lock you out of your own house. That is worth keeping in mind while you shop, because the right choice is mostly about reliability and fit, not features.
Start with your door. Retrofit locks replace only the thumb turn on the inside, so your existing deadbolt, exterior cylinder and keys stay as they are. They are easier to install and landlords rarely notice them. Full replacement locks swap the whole deadbolt, usually adding a keypad or fingerprint reader on the outside. They look cleaner and do more, but you need a door that fits and a little patience with a screwdriver.
Then pick the network. Matter support means the lock will work with Apple Home, Google Home, Alexa and SmartThings instead of one of them. Locks that use Matter over Thread are the ones to prefer: Thread is a low-power mesh, which is gentle on batteries, but it needs a Thread border router in the house, such as a recent Apple TV, HomePod or Nest hub. Wi-Fi locks need no hub, but Wi-Fi is harder on batteries.
Batteries deserve their own line. Most smart locks run on AA cells or a rechargeable pack, and the lock should warn you well before it dies. Check whether the model has a physical key backup or emergency USB power on the outside. If it has neither, a dead battery is a locksmith call.
Auto-lock is the feature people end up using most. It relocks the door after a set delay, so leaving it unlocked stops being possible. Pair it with a door sensor if the lock offers one, so it never throws the bolt into an open door frame.
Keypads and fingerprint readers remove the phone from the equation, which matters for kids, guests and dog walkers. Give each person their own code so you can delete one without resetting everyone. Fingerprint readers are convenient, but keep a keypad code or a key as a fallback for wet or cold fingers.
Finally, look at the app. Access logs, temporary codes and remote locking usually live in the maker's app, not in Matter, so read recent reviews of the software as carefully as the hardware.
The short version: renters should look at a retrofit lock with Matter over Thread. Homeowners who want a keypad should buy a full replacement with a physical key backup. Either way, make sure you have a border router before you start.
