In an earlier post, Chuck asked about my usual working hours when working with drillers. Short answer: it depends.
In most cases, I let the drilling company take the lead on working hours, as long as it was at least 40 hours/week - I was completely fine with the "lets work really hard the first four days and have a short Friday" option. My personal preference is to start at 7-7:30 and to work until 4:30 or so, depending on whether or not the drillers take a lunch break.
Exceptions included: 1) facility-specific hours, 2) residential areas (those are pretty much straight 9-5 so that we're not waking people up or hammering away through their dinner), 3) other oddball access situations, such as working on an island and meeting the shuttle's schedule.
Of course, sometimes you end up working longer hours. For one job that started out behind schedule and over budget (and didn't get any better over time), our standard working hours were 7 am to 6 pm for the drillers, with 45 minutes added to either end for me. No lunch. Why? Well, the equipment set up and break down took a minimum of 2 hours each, plus several of our big costs were rental-based, and we were just trying to make some headway in the project and get on with our lives. The driller and I each had the pleasure of getting angry phone calls from our respective managers multiple times a day about the budgets we were draining. Budgets which we had no input in and no control over....
Sorry, rant over. But I would say that 90% of the time, the drillers' schedules would be something like 7:30 to 4:30 - enough to be productive, but not outrageously long.