Three years ago I started bicycling to work.

It was a gradual thing. It took extra planning to ride--there were issues with clothing, issues with carrying stuff on the bike. I'd usually only ride if I thought of it the night before and the weather forecast looked good.

Wanting the exercise was what got me started. It takes me about 25 minutes to bicycle from my apartment to the office, versus 15 minutes to drive. So, an extra 20 minutes spent commuting gets me 50 minutes of aerobic exercise.

There are other ways to get exercise, though, and the bicycling wouldn't have persisted if it hadn't had other things going for it:

• It bookends the work day psychologically. The ride in to work gets me warmed up and ready to be productive. The time, motion, and effort of the ride home helps me unwind and leave the office behind.
• It's frugal. You can get a perfectly good bike from a bike store for just a few hundred dollars, and a few tens of dollars a year will keep it in tip-top shape essentially forever. (That's if you pay a bike store to do the maintenance. If you know about bikes and are handy with tools, you can probably cut both those amounts by an order of magnitude by finding a bike at a garage sale and fixing it up yourself.)
• It's gentle on the planet. I've read that there is no more efficient form of transportation than a bicycle. I've never done the math myself, so I can't swear that it beats using a mule to haul a barge down a canal, but that and sailing ships are the only possible contenders.
• It lets me get my smug on. Actually, a tendency to be smug about stuff like this is a character flaw of mine. I try to resist. But when gasoline prices spiked up in the summer of 2005, I'd ride past gas stations and look at those poor schlubs pumping $3 gas into their SUVs and be enormously reinforced in thinking that bicycling was unquestionably the way to go.

That smugness had another result, though. As the summer of 2005 drew to a close, and I realized that I was about to go back to being one of those poor schlubs (albeit pumping $3 gas into a Honda Civic and not an SUV), I couldn't quite bring myself to do it. On the other hand, I also couldn't quite bring myself to ride my bike in the winter's cold and dark. I ended up riding the bus in the winter. That turned out to work really well. I'd had no idea the local mass transit district was as good as it is. (I'll have more to say about this in the future. Our local transit district is doing really cool stuff with technology.)

My wife and I still have our car, and we use it when that's the handiest thing to do (which turns out not to be very often). The bus is handy for a lot of trips. Walking is the obvious choice when we just need to go somewhere and do something. But bicycling is always my first choice: it's faster, easier, more efficient, and more fun.

And that last is really the key. All those other reasons--the exercise and frugality and stuff--they're all true, but even the smugness wouldn't have kept me riding day in and day out. The reason I bicycle is because it's fun.