Think the longest straight was, well, about 9 am to around 8 pm, factor in the half hour lunch break, so around 10 and a half hours, but that was JUST ON THE INTERIOR. Needless to say, the interior was dirty as heck and i went through 2 full bottles of straight woolite, not the mix mind you, 2 full bottles of woolite. Made probably 20 gallons of the mix. Took out the seats, painted the feet cause they were all rusty, got out stains, tried to get out all the dirt but couldnt get it all it was so ground it, removed a milk shake from the foam and fabric of the passenger seat (what a frickin mess that was). It was in BAD shape. Looks pretty dang good now though ( that is until the window was left open a quarter inch and we had a monsoon, soaked everything, both seats, had a puddle almost in the floor, soaked everything, from a quarter inch opening in drivers door, what a mess).
All told, longest detailing straight was 10.5 hours, just on interior. AT that point i couldn't even fathom starting the outside....