For climbing up or down in the dark, get a hat with LEDs in the brim or a light that clips onto your hat brim. It will always put light where you are looking hands free. I will climb in the dark if I don't want to spook any nearby deer, but sometimes you just need the light to be safe.

I was in a tall tree last year and some heavy fog came in at sunset. It was really spooky coming down. Even with the light, all I could see was the tree trunk and fog. I had no idea how high up I was at any point of the descent. I knew I was at the bottom when a weed flicked my ear. The hat light was a big help making sure I had good bites in the tree.