It doesnt take me very long at all , as we dont try to make the panels straight as all get out .
We are a production shop not a show car shop, we make them presentable.
For instance most repairs I get are front ends, so some of it is new parts and repaired parts.
I feather edge and prime my repaired areas and let primer set over night , then in the morning I will block sand my primed areas , then sand with 320 on a DA, then blow it off, back it in the booth , wrap it up , then wipe it down with wax and grease remover, tack it, seal it , base it , then clear it , then turn it on cook cycle,.
I can usually do 2 front ends by noon( get to work at 8 AM) , so thats 2 hours per car total from prep to paint.
That encludes blending both doors also.
Like I said I feel like a robot any more as I have painted for 30 years. I could do it in my sleep, most time when I am spraying i am thinking of what i need to do to my HotRod .LOL

And I never get comebacks , unless they wreck them again! Its how you make the big bucks now days