That $60 office call in Tacoma line hit me hard because I've been on both sides of that mess. Back when I was green I'd pull everything apart before even checking if the monitor cable was loose, and I ate the cost more times than I want to admit. Learned the same lesson you did, just slower and with more angry clients staring at me. Now I check the dumb stuff first, cables, power, the little things, and I save the deep stuff for when it's actually needed. You live and you learn I guess.