@Joe_67 So with the 3M kit you get about 6 months give or take? I had good luck with the blue boxed Meguiars headlight restoration kit. Its good for light oxidation, but anything heavy requires various sand/cutting discs. With that it would last about 8 months before the protective coating they give in a can starts to disappear.
Played around with the Spring Compressor kit I purchased a few posts up. Its FANTASTIC, no signs of bending or anything! I have to say, its very sturdy and well constructed. It may be due to the design of the clamps, but compressing the spring goes great but when you loosen it there isn't any wiggle room to get them free once the struts assembled. I tried about 3 different times before throwing in the towel. Going to come back to it tomorrow (after the frustration started kicking in), and give it another go.
I also didn't tighten the cap on the jugs used for the old tranny fluid. Went to grab something, knocked it over and fluid went everywhere.
IMHO, any "protective coating" is something like a red herring/snake oil. These cheap plastic things (OEM or not) will oxidize and pit no matter what. So to me it's just a regular maintenance item. If the headlight assys have heavy pitting and oxidation, and if you don't want to buy new ones, then you sand the sh** out of them (5-600 down to 3000). Then you just keep them polished on a regular basis.
A lot of internet advice ends with clear coating them to keep them nice. But the clear coat dies too and then it's a bigger mess. My Envoy has that problem - someone cheap clear coated them and you can see it just break down and flake over time.
But it's not terrible, so I haven't done more than a 3000 sand on the though. I figure if I just do the periodic 3000 wet sand and polish at each oil change (just MY marker) followed by a polishing compound eventually the flaking clear coat will be gone. In the mean time it keeps them looking and shining well enough.
I have to start taking before/afters (which I don't).