At least about the products they sell. I have a 5hp briggs that needs a carburetor diaphragm so I went to a small engine shop with the part, handed it to the man at the counter, told him what it was for and asked if he had one. He asked if I had the engine model and serial #, I just took it back and walked out. Came home and searched on the web, there are 2 possibilities and it's quite obvious which is which. Back before the computer age a parts person would have just walked back to the shelf and got one.