The job of the furnace is to keep your house warm, while the job of the furnace repairman is to ensure that it does the best job. Hence your furnace repairman is as important as your furnace.
This is why you need to hire the best furnace repairman and analyze their work regularly. If you notice something odd about your repairman, you should immediately find a new one. Here are some of the sings that indicate that you require a new furnace repairman.