I have a 2011 rear hub bike that came with fitted lights that ran of the battery, which are very useful, but more to be seen by than to see with. I still put mine on, but augment them with the excellent rechargeable lights that you can get now, and are very reasonable, a bright flashing rear light and a much brighter front light that is good enough to ride on unlit roads. I angle the front built in light to light the verge ahead and the brighter rechargeable one the road ahead. They cost relative peanuts. Mine are Moon but there are other makes that are just as good. If you are going to ride in the dark you need to get some purely for your own safety.