There are several power saving levels available on the ESP32. At the deepest power saving level, it's actually quite efficient, but it will also have shut off p

There are several power saving levels available on the ESP32. At the deepest power saving level, it's actually quite efficient, but it will also have shut off power to the RAM, meaning that if the device wakes from a timer or an interrupt, it has to do a fresh boot. There is a power saving level where the RAM is kept powered but most of the rest is powered down, and that is the one that is less efficient than some of the competition, so if you require that then you'll get a lot less battery life time. It's somewhat better in the latest ESP32 models.