Its a silly question but I wonder if anyone else experience this... Our plants make thermostat devices, almost all of its parts made in house so we have a lot of different machines, new and old. Here is the strange part... More often than not, when I get service calls, within a span of 2 or 3 days, the nature of the problems tend to be very similar. Yesterday and today, I got four service calls, all for different machines; a metal-cutting saw, grinder, roll metal dispenser, stamping machine. All of them had a bad limit switch. Something like this happens to me with photoeyes and safety relays. What gives?