I am a general contractor. I bring a plumber to do some modifications. Appointment time is 9 am in a condo. I arrive on site 8:45, plumber buzzes the condo at 9 am, buz him up. He takes a look, need parts not in his truck, off he goes to supplier. 45 minutes later back onsite, completes modifications, leaves site 1 pm.
Guess what, clock started at 9 am and stopped at 1 pm. Time to assess, get parts and clean up and load his tools back into his truck are all billable.
Now I could have got him to come and give me a set price but he would have also included travel, setup, time to get parts and clean up time in his estimate and proobably a hour or two extra time to do the work just incase.
Most professional services include setup, travel time, material pickup, cleanup and unload/load tools as billable items. Oh don’t forget the notorious “truck charge”.
Yes I know Its different but its also the same.