I run really bright lights on my bikes, but I usually carry a cheap Chinese headlight/taillight set. Why? I like to say it's for redundancy, but the chances of my DiNotte lights failing are pretty small. No, I carry them so I can give them to ninja cyclists I encounter. I've given out 5 sets in the last few years. Sometimes the riders are really appreciative, and sometimes they look at me like I'm nuts, but I figure if I give them the light and they use it they may not get run over.