I worked in the old times of NAPA, when every parts store was open until noon on Saturday and closed on Sundays.  Note:  Well known that every parts store in town was open 8:00 a.m. until noon.
When did we do the most business?  11:30 until around 1:30p.m. It was a very rare Saturday when we left at noon. I guess lots of folks wanted to sleep in. 
I even had a fellow call asking us to stay open later because he "really needed" brake shoes for his work car.  "How long until you can get here?" I asked.  "Well I want to finish watching the football game first."  I wasn't sorry we missed that sale!!!