If you plan on commuting throughout the winter it is more than a little likely that you will get caught in some less than favourable weather from time to time. For this reason it is advisable to choose a light that is pretty robust and fully waterproof. Again this might require a little more investment initially but will be worth it as the light won’t fail the minute you suffer a downpour!
It is also advisable to choose a light with a large power button, it makes it far easier in the depths of winter when you are wearing gloves.
Most lights will feature just one large button that will run through all of the various settings per touch, it will then require one long push of the button to switch it off – this eradicates the chance of being plummeted into darkness by mistaking powering the light off!