The watch doesn't "require" charging for fitness functions, unless I'm reading what Casio announced wrong. According to them, the watch will recharge enough with the solar panel quickly enough to use the fitness functions for 7 hours a week(1 hour a day). Sure, for some people that's not enough, but I imagine for a lot(like myself) who only do 1-2 hours of actual exercise where I want to use the tracker per week, that's more than enough. I can't wait to order it, and I plan on never using the USB charger - will see if that proves doable.