like pretty much everyone has said, it comes down more to time required than distance traveled. I started commuting almost 2 years ago in southern maine going 18 miles each way. About 50 minutes in the morning, hour and 5 in the afternoon. That was just to meet a ride, as we work all over the place. In the warmer months if I wake up earlier, I'll just start pedalling. 40, 42, and 53 one way commutes this summer. I did get a ride back afterwards though. I work in construction so appearance is not as crucial as business setting. but Ive done everything to make the commute easier and faster. Added aero bars, wear spandex and store a couple days worth of clothes in the job trailer so I can take off the rack and panniers.