A few years back when I had some well trouble, the well company sent 2 service guys out at $40/hr. each. It takes about 30 minutes to get to my house from the well company. They wacked me $40 travel time. When I expressed my disgust to my father about this he said it is not uncommon for service companies to charge their hourly rate for travel time from call to call.
I'm in a service related field (coin-op amusements). I don't charge my accounts any service fees simply because I'm making money from them on a weekly basis anyway. However, if I do get what we refer to as "outside service" calls (homeowner, or some business that may have their own equipment. basically someone I do not do business with on a weekly basis) I always account for travel time.
I would say raise your hourly rate 5 bucks if anything, but if questioned about it just say it's overhead related. The higher cost of fuel affects every aspect of you business overhead to a certain degree. I'd also imagine freight costs would be figured into the cost of the part charged to the customer as well, so no need to compensate for that.
In my experience with the rising cost of fuel, my "inbound freight" costs I get charged when I purchase something new from any of my distributors has not gone up. However, my distributors now charge a minimum of $25 for each machine they deliver to me from their warehouses. If I make the trip to pick up, then it's my own travel expense.
Hope this helps
