Two weeks ago I spend a week with my family on St. George Island. My please was detailing their cars. I discovered a 'short cut' for big pickup trucks and suvs. I completely finish the roofs (i.e., wash, clay, polish and wax) before doing anything else. My rationale I am doin g a lot of standing on latters. I rather do same before I am tired. Therefore, I do the roofs first. I find it is safer and quicker. (I spend a lot less time carrying the latter around.)