I do it both ways and haven't really seen any difference. I know some get technical about how to charge li-ons but really the battery is so small that if your don't top off fully and don't let it discharge fully (I've heard arguments on what's best)... first where is that charging sweet spot and even if you knew it would be such a small area so I just don't think about it. The batteries... both PCC and Erolls have lasted me so long longevity-wise that its a non-issue. I haven't had one reach its life span yet. Everything still works as well as when I got them. True, I do use and rotate a lot of them but, still, using 10 at $10.00 a piece is $100.00 and I've heard of big batts near that cost that haven't lasted this long. Anyway.. I'm rambling.. I promise I don't work for Joye or Ovale LOL. Anyway, trying to say do it however you like really. As I said, I carry a lot of the charged up and just carry the PCC as a fail safe in case they all reach their life span at once because I bought them pretty well all at once. With all those, I don't bother recharging while out so the PCC is never carrying one. If I carried two, I think I would probably take the fully charged one out when its done charging. They say you don't have to but I would... I just don't like leaving a battery that's done still in a charger. But, that's just me. I would just carry a little knife case or something to carry the two fully charged ones in.