Cateye presents a new light that you will never have to worry about turning off or on, it is called the Reflex Auto.
The Reflex Auto light is used as a tail light, and has optic and motion sensors. So when it is dark outside, and the light detects movement, the Cateye Reflex Auto will turn on. Using active and passive safety, with active safety by your traditional bike light, and passive is suited by CPSC reflector.
You definitely have options, with a variety of mounting options, 180 degrees of visibility, and 5 light modes. The front Reflex Auto will last up to 60 hours, and the tail light up to 120 hours.