Every smart lock we fit comes with physical keys

Every smart lock we supply comes with physical keys in the box, and we hand them over when we fit it. The key opens the door the old-fashioned way, without the battery, the app or a code.

That is true of every lock in our shop: the front and back door locks and the fingerprint lock for room doors.

A flat battery does not come as a surprise. Once the battery drops to about 20%, the lock tells you every time you use it: you hear the warning from the lock itself as you open the door. The app on your phone sends a low-battery notification as well.

So there are weeks of warnings, at the door and on your phone, before the battery would run out. Changing the batteries takes a couple of minutes and needs no tools beyond a small screwdriver on some models; we show you how when we fit the lock.

The key is for the rare day everything else has been ignored: a warning nobody heard because the property was empty, or a holiday let between guests. Turn the key and the door opens as it always did.

For a rental, keep one key somewhere safe that is not on the property, and give your cleaner or manager a code rather than a key. That way the key stays the backup it is meant to be.

Not under the mat and not in a box by the door: a key left at the property undoes the point of a smart lock. Keep them where you keep any other spare key, with someone you trust, or in the office for a managed property.