my driver side headlight is starting to get that rough hazy stuff on the outside what is the best way to fix this.......and what causes this to happen

 

There's a thread in here:

https://acurazine.com/forums/3g-tl-2004-2008-93/3g-tl-garage-faq-3g-tl-newbies-553554/

Something like headlight restoration.


Not sure of the cause. UV? Salt? I've had my '02 for almost 7 years and my headlights are in nearly new condition.

 

A fine polishing compound and a little rubbing should take care of that.
LOOK HERE --> https://acurazine.com/forums/3g-tl-2004-2008-93/g-085-diy-restoring-hazed-cloudy-headlights-710313/

 

It's my understanding that not only will the headlight enclosure fog again, it will do it more quickly because you've cut down into the softer interior of the plastic. I would suggest that you install "clear bra for headlights" immediately after you finish clearing them. It will protect from both UV and oxygen/ozone. You can get the coverings from X-Pel or Extang, to name two, they aren't very expensive, and applying them should be fairly easy.