I finally met the guy who paid me $40 to fix a camera he'd already fixed himself
A fella walked into my bench space in Boise last month carrying a Pentax K1000 in a ziplock bag, all in pieces, and he smiled and told me he'd watched a repair clip online and thought he could do it faster. He handed me the bag plus $40 and asked if I could put it back together before his trip, and I counted 14 screws rolling around in there with two of them clearly from a different camera. How do you nicely tell someone their DIY job added three hours to my night?
Had this exact thing happen with a Nikon FM2 and the guy stood there watching me work, which made it worse. What worked for me was just being straight about the time and letting the price do the talking. I told him flat out the screws he mixed in cost him an extra hour because I had to sort which ones even belonged to his camera. Then I handed him a written sheet with the hours broken down, parts, and what his DIY job added on top. He got quiet, paid it, and honestly he came back two months later with a different camera and didn't touch it himself that time. Being nice about it just gets you walked on, so say the number and let him sit with it.