Agree with above. Flashing for conspicuity. Steady to help others judge your position and speed. The steady light isn't really needed during the day, but helps a lot at night, IMO. Intensity is a major factor. In bright sunlight, you need a very bright blinky. Riding in and out of shadows during a sunny day, a bright blinky really helps drivers spot you when you happen to be in a shadow while their windshield is brightly illuminated by sun. At night, it might be too much and can dazzle drivers.