Cab shifts usually run from about 4 or 5 a.m. until 4 or 5 p.m. and then 4 or 5 p.m. to 4 or 5 a.m., so know that you will have a harder time hailing a taxi within 30 minutes or so of the shift change. Take notice of the off-duty light, which is on the side of the center number.