Up to 15 years is what they say. That is probably a very optimistic estimate, but I would not be surprised that it could do standby for a very long time on a single Lion AA cell, as there is no screen.

Solar and kinetic charging are bulky and cumbersome. At this price point they would probably be shoddy and unreliable.

I keep a charging "brick" in my car, and just top it up every month. In an emergency, I could charge my phone/tablet about a half dozen times. I figure that's a lot more useful to me in a genuine emergency I'm likely to experience, than this toy.