Refinishing headlight lense vs buying new/near new headlights?

[tmontague]

I've sanded, polished and then clear coated my headlights on both my card and have had no yellowing or clouding come back. If you do it properly it will work for a decade. The key is to re coat with a non yellowing uv resistant clear coat with multiple coats applied. The sanding strips off the faxtory coat which is why the yellowing and clouding happens.

Like you said, not much will protect against rocks and bolts though.