The camera one, by the front door. You check the little clip on your phone twelve times a day and mutter about the delivery guy who leaves the package leaning against the wall.
Here is what you don't know yet. You are watching the most ordinary footage in the world, and it is a treasure. Fourteen seconds of your kid coming home from school, dropping the backpack the exact wrong way, fighting the key in the lock like it personally insulted him. The dog's nose fogging the lens. Your own hand, reaching into frame with the keys, wearing that ring you'll lose in a few years and never really stop looking for.
You think the doorbell is for catching porch pirates. It is quietly keeping something else. Every time someone you love walks up those three steps, it writes it down. The way your mother pauses at the top to catch her breath and pretends she isn't. The friend who always knocks anyway, out of habit, a half-second before pressing it.
You will not watch these clips for the packages.
So the next time it chimes and you sigh and pull out your phone, look a little longer at whoever is standing there squinting up into it. That's the whole thing, right there, in bad wide-angle color. Don't rush to the door. Just watch them arrive for a second.
You'll be so glad you saw them coming.