Originally posted by Bigtime
I'm not sure what good a mirror does though, seems to me if someone is bearing down on you or is too close by the time you see them it's too late.
There are two situations where I find a mirror indispensable. One is when merging left across multiple lanes as I approach a place where I'll need to turn left. It's much easier to hold my line and do frequent quick checks of the next lane with the mirror.
The other is whenever I approach an intersection -- any intersection. I *always* check to see if there's a vehicle approaching me from behind that could conceivably right-hook me. This is one of the most common bike accidents, and when you cross hundreds of intersections a day, many days per week, the odds start to mount that you'll get hooked eventually if you aren't alert. The mirror habit helps.
I use a Take-a-look glasses-mount mirror. Wonderful design.
RichC