Remember my buddy who does HVAC work telling me about a retrofit last month. His senior partner almost blew a gasket trying to figure out the smart thermostat wiring, said it was pure nonsense. But the home owner paid them triple their usual rate for the two hours of headache. That same old partner now carries the manual for those things in his truck, grumbling the whole time but still doing the jobs. He admitted the extra cash bought his wife a real nice anniversary gift, so the fuss was worth it. Sometimes the grumpiest ones come around once they see the new tools just mean better paydays.