They won’t run long on battery if you try to run them constantly. This is why they support deep sleep, which allows you to instruct it to shutdown until an interrupt is fired by either the real-time clock, or some other input. Typical behaviour for a device like a temperature sensor is to wake up, report the temperature, and then go back to sleep either for a set duration or until a significant change in temperature is reported by some lower power components.

Thank you - I’ve been playing with this and it’s really neat. It’s an amusing workflow in ESPHome as you have to work out when the device is awake to run an OTA update.