Hmmm, looks like this conversation shifted somehow from "how far do I travel..." to a heated discussion on carbon footprints...! Not that there's anything wrong with it, just an interesting observation.
Here's my "jumping in the middle of an existing conversation, for better or worse" answer to your question Mr. English Roofer:
As far as is practicle.
Makes sense no?
Pay me more, I drive more. Pay me less, I drive less. Give me referrals, I drive more. Gas price goes up, I drive less.
Ok, sorry for the joking here. Honestly however, I have no set limit for drive. What I HAVE noticed however is priced differ from city to city. For example, I'm in Calgary, 3 hours north, in Edmonton, roofers out there charge on average %15 less for their jobs. Hard to compete with if I have a %30 profit margin, am challenged to drop it by half, then have to incur travel expenses on top.
So at the end of the day, I'll drive about 1.5 hours to get to where I need to get to. Any further and I'll be more likely to compete with the neighboring city's lower prices (haven't figured out yet how they do it though).
I've got a bunch of interesting stuff posted on my web site, feel free to take a look.
www.calgary-roofing.com