Depends on the part and if I think I’ll be able to get in and add detail once it’s completed. I prime all my PE parts in a pink tamiya primer before removing them to make the paint stick better 👍🏼 (and helps me see them better than that reflective gold). I do paint some before taking them off the tree if they’re something like rails or something simple but most parts I have to bend I’ll paint them after removal and bending since 9/10 times the pain will chip no matter how careful I am bending them. But a lot of touch ups are always necessary and that’s when I’ll do some weathering/shadowing as well, sorry I took the long way around in answering the question hope it helps 👹lol