the most important part of this process ( the one most people forget) is applying a UV resistant top Coating...generally Auto motive clear coat works well.
I'm pedantic enough to spend $30 or so for each car before they have issues*, and apply Pre-cut 3M film... essentially PPF...
*2 cars back(2005 neon), I had to replace the light assemblies, as they had that kind of damage, but also lots of fine cracks. I got film for the new lenses before i installed them.
both cars since, (bought 5 years old,~60k mi) they've luckily still been in good condition, and Applying said Film is one of the first things i do.
Just had to put a new set of films on the Cmax, after replacing a stubborn leaking/condensating R headlamp assembly. place i order from sells the pre-cut film by the pair (Can't just get a left or Right cut.), so replaced both.
I did the First job on the neon back in '12? last I saw the car ( some time in '18-19) it belonged to my buddy's active duty little brother, and the lamps were still as clear as they day i put them in.
