Cam And Lifter Hardness Testing

I have done many cam break in's, for myself, my family and other people, I have had only 1 go bad, and it was an old MP cam, slightly used, and don't know what decade it was from, I think most people don't understand the process, the engine needs to be primed, the distributor must be right, fuel in the carb, not cranking until the bowls fill, and must fire immediately, no cranking for 10mins.