1) Its easier to find a guy to do the bodywork than it is to find a guy to paint it. Its the bodyshop pecking order with the painter on top. Difficult to find anyone to do either on a steady basis.
2) I farm out my plating but prep/polish pieces myself before and after.
3)I purchase my globes and decals
4)I purchase parts from suppliers when I can't locate originals
5)I do my own bodywork and paint
6)I have my stripping and striping/lettering done
7)I pick and buy the pumps I do and restore them the way I like them to look. I try to stay away from restoring other peoples pumps or doing custom orders.
8)Some peoples taste in how they want the pump to look is not commensurate with their skills so they farm it out. Others who actively sell pumps farm it out for expediency.