It’s normal for headlights to slowly dim as they age.
Headlight restoration or plastic headlight restoration is the act of restoring aged headlight lenses that have become discolored or dull due the degradation of the original factoryUV light and other environmental factors such as road debris impact (stones, sand, etc.) rain, and exposure to caustic chemicals. We want try to avoid crazing, wherein polycarbonate lens will eventually develop small surface cracks and discoloration.
Additionally, headlight restoration if done right with the reapplication of a UV protective hard coat extends the usable life of the headlight assembly and can be repeated if necessary , also considerably “greener” than disposal and replacement of headlights, reducing land fill and microplastics entering our environment.