Three: a Busch and Mueller dynamo tail light (toplight line brake plus) on rear rack, a 2nd gen Cycliq Fly6 series cam/light combo on seatpost, and a Light and Motion 360+ on the helmet. The latter is the older, better designed, more visible, built in reflector version, not the new one. Not sure what they were thinking when “improving” it, but I digress. My commute is 75% MUP and I turn off all but the dynamo light for those stretches. For traffic, day or night all three are in use. Overkill, perhaps.