- Twice-daily exercise without going out of my way.
- Even if biking takes slightly longer than the subway, it's a completely predictable length of time, determined only by how fast I pedal. The subway often has unforeseen delays.
- No more waiting on humid platforms or crowding in on rush-hour trains.
- Saves money: I haven't bought an Unlimited MetroCard yet.
- Have to change clothes upon arrival at school, adding to the effective door-to-door time even further.
- Less convenient to go somewhere other than straight home after school (though not such a big deal since I can leave my bike at school overnight).
- It might start raining during the day (not really a problem - see above).
- The subway was where I did all my extracurricular reading, so that's not happening anymore. (Reading a book on a bike would be dangerous. So would an audio book, to a much lesser extent.)