I bring my cellphone for photos and GPS anyway so I'm already committed to maintaining it's battery.? That is one thing I like about Spot3 over others is the use of regular batteries vs recharging.? A spare set of AAA batteries weighs very little, but if I'm on a short trip I don't even bother as I know with a fresh set of batteries and turning it off at night it will function for at least 3 weeks.
That said, power packs are getting better and better so recharging isn't the concern it once was.