I was having a mysterious electrical problem that I could not figure out after hooking up my replacement starter. The battery seemed fine but it would not turn over. I pushed the vehicle 2 blocks down the street to a mechanics shop and he traced the problem to a loose ground wire that he reattached to the chassis. I would never have been able to figure it out on my own, and he needed a 2nd person to assist in the procedure so I spent over an hour at his shop helping connect wires while he checked for voltage at various locations in the wiring harness. I think it cost me about $50 to $100 for the expertise.