I don't need 18 days. I'd like to be able to go on a trip without worrying about bringing yet another charger though. So for me, getting to 6 or 7 days is the sweet spot. I'm guessing the AWU will hit 4-5 in low power mode for people who don't use it intensively. But of course the battery will only get worse over time, and if you're running in low power mode that takes much of the value out of having an AW in the first place.