@KayOhtie @TechConnectify confidence is key and believing in the supremacy of cause and effect. Also having access to trouble shooting tools. In software a lot of times it is strace and tcpdump and trace and so on. For hardware for me a lot of time it is having spare parts so I can swap in and out. I understand real engineers can use oscilloscopes and circuit tracing and signal analyzers etc. even for stuff like the turtle tank smells bad from time to time, an experimental method works.