These folks helped me diagnose and fix my appliances several times of the past 10 or 11 years.
Typically
-I call them; explain the problem and they go over the possible solutions. They are at least a 30 minute drive for me but they always figure out the fix. One call was for a cook-top set of burners that stopped igniting. They had the parts and explained how to do it. Another time it was a type of fuse in the dryer. They had the part and even helped me when I got back to the house when I had trouble. Several times it was the dish-washer. (we are hard on our dish-washer) They helped me with that dishwasher 3 or 4 times; to get it back running with all sorts of parts over the years. Sometimes; the problem didn't require parts from them, just a treatment that they explained thoroughly. I probably got an extra 6 to 7 years out of that old dishwasher before it finally gave up the ghost.
I've always considered it a high cost and security risk to have repairman come to my house. We've all heard the horror stories about Vegas repairmen and at the end of all of those stories; you hear the crazy price someone paid. I really like these folks because they help me avoid both problems and get the appliances up and running.