One of the projects I am doing at the airport is replacing the tubing in my spark plug tester. All the tubing became brittle. I bought a repair kit from the manufacturer and started into the repair. As it turns out, I have to take quite a bit of the parts out to get access to the tubing fittings. Being no idiot, I completely photographed the inside so that I can remember where each tube went. This is going to be quite a chore.