Advance Auto Parts (AAP -0.52%) shares have been smashed this year. But before buying the dip, Motley Fool contributors Jason Hall and Tyler Crowe think investors should look at AutoZone (AZO 1.33%) and O'Reilly Auto Parts (ORLY -0.83%) first, and explain the one number that breaks down why these two have been far better investments than their struggling competitor. 

*Stock prices used were from the afternoon of July 7, 2023. The video was published on July 16, 2023.