They are listening all the time. Presumably 'just' for the wakeword. Better yet, Alexa listens to everything you do inside your house, and the Ring Network list

They are listening all the time. Presumably 'just' for the wakeword. Better yet, Alexa listens to everything you do inside your house, and the Ring Network listens to everything you do outside your house. And both of them are connected to the power outlet, so the 'but battery depletion' excuse doesn't apply.