My commute is 10 miles each way.

I commute for several reasons:

1. Lose weight (currently ~270lb)
2. Save gas money
3. I get to ride my bike.

I'm usually pretty busy with other responsibilities on the weekends, so my weekday commutes give me opportunities to get on the bike and ride.

I live right next to the foothills, so on the ride home, sometimes I'll do a few climbs to get my heart rate up, and add a few miles.