Which ad hours work best?

The hours that work are the ones when there is still room and someone answers, which is usually before the full service, not during the peak. Closed hours never work, even if the click is cheap. Cross the week’s occupancy with the hours the phone is picked up. The ad lives in that overlap, not across 24 hours. You advertise in the small hours because the cost drops. Nobody books a menu at four in the morning for a venue that opens at one. The ad schedule set to the overlap of gap and response, saved on the campaign. A week later you check whether the messages landed there.