Bikes wear out and need service and eventual replacement of parts. But consider what you spent on generator hubs and the lights a capital investment, since those can be transferred bike to bike for nearly forever.

I don't know what insurance costs in Michigan, but when I surrendered my plates, it put about $1,000 cash into my pocket. Add fuel, tires, and basic maintenance an I figure it cost me about $50/wk for a 100 mile per week commute. Of course, if I simply stopped commuting in it, but kept the car on the road I'd be saving much less.