@
ThermionicScott, exactly how I feel. I could ride one evening, knowing I charged the battery yesterday and I should be fine. And then it conks out, and I remember, oops, I charged it the day before yesterday. That's not OK. I kinda-sorta know the charge state of my light, but that's not good enough. With a dynamo-powered light, I absolutely know it's going to work as long as the bike rolls. That's a huge difference (for me) from kinda-sorta knowing.
At the moment, my commuter bike doesn't have its dynamo lights installed. Long story. I am using a B&M Ixon Core headlight. It always shows the charge state, which helps. It has a 1-5 readout. And as far as I can tell, it seems to be able to go three or four days between charges, so my extra layer of safety is my practice to recharge it every two days.