Personally I don't like rechargeable headlamps because they don't last long enough. I'm often out riding long enough in the dark that I need more than 2 hours batter life. I use a flashlight that runs on a 18650 battery and carry a spare battery with me so I can change out the battery when the first runs out. And then recharge both when I get home. Charging takes about 5 hours, so if I put them in the charger when I get home, they're ready in the morning. No big deal...

The tail light I'm not so concerned about because 2xAAA will run for more than 15 hours, probably closer to 20 hours, without much performance degradation. Plus batteries are readily available at supermarket if it really comes down to it.