I have to emphasize the importance of a good front light.

While driving home this evening, I saw a cyclist turning onto the street ahead of me -- good distance, nothing to worry about, and had a rear blinking light.

I passed him about a block later, and once I did, I realized that I could hardly tell where he was, especially since I had flipped my rear view mirror to night mode. All I saw behind me was the headlights of the SUV; I had no idea whether it was yet safe for me to move over again.

As it turns out, I didn't cut him off -- I had given him plenty of space. But, if the cyclist had a good headlight, I wouldn't have had to worry so much.