I replaced my windshield 11 years ago with Lexan.It Looks as good today as the day I replaced it.
I posted a "
How to Replace your Windshield" thread at the time
Note:
I use spray window cleaner and lint free towels only
I try to hose off any dirt before wiping or cleaning
I ONLY use horizontal strokes when wiping off the cleaner ( I think this helps avoid/minimize micro scratches in the scratch "resistant" coating.
I have used my wipers on occasion but I wipe off the blades to insure no dirt is on them which could scratch the windshield.
I do use Rain-X which helps avoid having to use the wipers ( Rain-X does leave a coating which can give a bit of a haze on cool nights nothing major)
Since replacing I've heard a number of rocks bounce off the windshield without leaving so much as a mark so it was definitely worth the $125 I spent at the time. I would probably be well over $1000 in replacements if I had used glass.
Hope this helps,
Mike