Keys.
We have loads of them.
That's only one board.
We have another.
And that's before all our personal keys.
And all the ones in various drawers to go with houses we lived in previously.
Or cars owned 30 years ago.
Keys of every description.
Probably.
Now you can get doors that open with an app on your phone.
How good is that going to be!?!?!
Until your battery goes flat.
And your charger is indoors.
Behind the keyless door.