People have a varying degree of night vision. You may need a more powerful light than others do. I use a L&M Urban 800 on the bars and a L&M 360+ on the helmet. Both are used at their lowest powered setting almost all the time which are 225 and 125 lumens respectively. Fast downhills I will use the highest setting. Newer models are 900 and 1,000 lumens. I have tried both Nightrider, including the Boost models, and Cygolite brands and prefer L&M. Between myself and my wife we have 10 of them for our 4 bikes. The only thing I wish L&M had was a flashing light for day time riding. They have a pulsing light which isn't quite as much of an attention getter during daytime riding. I use it anyway as my lights are on no matter what time I'm riding.
I also highly recommend a helmet light both for seeing around turns and for shining directly at drivers when necessary to get their attention. Even with all the lights, drivers coming out of side streets sometimes need that light shined directly at them.