Once I was supposed to repair various issue on a massive Eminent organ (grand theatre 2500 IIRC) with kind of sweat...especially once I open the back, with literally two layer of metal frame on hinge (about 2m square each) dozens and dozens pcb...hundreds meters of wire ... total collapse in my mind
Then, after reassembling myself and trying to elaborate a strategy to handle this mess, I saw a stapled pocket on the inner side with a binder slipped in. everything was there !!! what a relief !