Yeah, I ran into that all the time when I worked for a service company. Our trucks were stocked with an insane amount of parts inventory to the extent that we could do a typical 200 amp service change on the spot. We carried somewhere in the area of $10K worth of inventory per truck. Still, it was inevitable that we'd encounter some strange doohickey that we didn't have.
Our company's policy on this was really quite simple: The customer could pay us for our time to make a special trip to the supply house or we could order it and return at another time to replace it. In almost every case, they would opt to just pay us to go get it since they had already taken off work to be there. More importantly, whatever we were there to fix was critical and couldn't wait anyway, like a heat sequencer, etc.
Just returned from looking at a job and they suggested doing the work T&M. I was OK with that but made sure they were informed that the "T" part meant ALL of the time spent towards the project not just the time I was there. Layout, list making and material runs are for sure considered billable labor. I usually throw in one-way travel and don't hit them for office/billing time though.
zback as an EC, I did a lot of T&M for a few good clients. Office/billing time was not chargable directly, but layout, drawings, etc., was billable. Both the clients and I liked the fact that T&M eliminated the estimate/proposal & acceptance paperwork, and provided prompt service.
Material pickup was billable, rate was dependent on helper or mechanic/j-man making the trip. Most materials were delivered to the jobsite by supply houses, sometimes daily.
I think that website needs to be boycotted. It gives the average "web surfer" the wrong impression. I'd like to see the fellow who runs that website make a living on those prices:)
All this talk about billable hours makes me laugh ( or cry). How many hours-days spent doing estimates and then never getting the job. UGH! Spent many nights tossing and turning to try and give customers fair prices, yet still trying to make a living.