for fall/winter/spring I ride to work in the dark and twilight on the way home. all of my cool weather gear has reflective strips. tail light is a must, I also have a helmet light (nite rider HID) and a handle bar light (cheap nashbar LED), it's not a matter somuch of seeing where you are going but rather the cars and traffic being able to see you.
since I live in the middle of the desert and even in the spring we have very little rain I have not needed fenders or mudflaps, I did add a rack to my commuter bike with a rack bag and then I use a backpack.
I've been commuting for a bit over a year now, it's always an adventure
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