A former employer owned a combined cycle power plant -when they were having issues (not huge ones, but weird issues or gauge readings) they’d call this old timer and he’d come in walking around ask the operators to make some settings changes and be listening the whole time. And he’d come back and be like “hey the second stage compressor is out of balance” there were all sorts of telematics and manuals, but he could tell what was wrong just by listening…that was invaluable