I use 2 lights on the bike and a helmet light. That’s for on- and off-road for the same reason: the helmet light is the most useful of the lights I use. I aim it into corners where lights on the bike won’t reach. I use it to warn drivers who aren’t paying attention. I use it to spot light things...it has a tighter beam... I might not want to ride into. Currently there are spots of ice on the road that aren’t illuminated all that a well by the wide angle lights on my handlebars.