Did one last spring, the handy did a fair job but missed some wire protection, some bushings and landed the N and G on the same bar in the sub,, with no bond to the can, the branches were grounded (not separately)but,,, I went home and got a bar, some pipe for the riser, got 1 N under a screw, put in 2 gfci and a switch to an entrance in a shed as I recall. I must have opened the box at the main to make sure it wasn't double wired under screws.
He had all the grounds twisted, I see a wire landed on the devices, didn't check it all. I had a helper and it still took better than a couple hrs to fix most of the violations. Added a rod too.
I ran across a couple un grounded boxes lately.