Here's my take, as one of those pesky commercial building engineers that everyone loves to hate...
Most contractors, at least here in the D.C. Metro area, both resi and commercial, charge a 4 hr. min. which includes travel, which in this area can eat a lot of time. I hear complaints from people all of the time about this, but I understand completely. You also have to have a well-stocked truck to be able to handle most run-of-the mill problems you will encounter. Also provides opportunities to upsell, as long as it's done ethically.
Mt. Falls, Va.
"Not a sermon, just a thought"
A licensed electrically-related individual