A little over a month, and on Monday the rear light failed in a bit of rain, I only realised that had happened only after a car beeped at me, nearly hitting me. I assumed others hadn't followed instructions on the implementation of the rear light in the reviews I read prior to purchase. I think the chance of failure can be reduced if I get mud guards fitted to the bike, this was purely used on suburban roads, so nothing off road here, just main roads. I need a guaranteed rear light to work, the front light is good, but you're depending on the back to notify others of your presence on the road, in these darker nights and mornings. so one star.