Traditional shop hours are Sunday through Thursday 8:00 or 8:30 a.m. to 1:00 p.m. , 4:00 to 7:00 p.m. , and Friday 8:00 or 8:30 a.m. to 2:00 or 3:00 p.m.
Merchants have other activities during the day, that's why they take a break for a few hours.