I was not trying to be condescending. Perhaps I should have worded it better. Knowing how to use tools is not the same as diagnosing a problem and deciding on a repair. To diagnose a problem you must understand the system that is not functioning properly and know what to do to make it work properly. Tools are only a part of the solution. The key is the knowledge. If you don't have that all of the tools in the word are not going to help you. Not every owner possesses the necessary knowledge to do repairs whether in their garage or "on the road".