Somebody told me that it’s not a good idea to use those cardboard sun visors for your car because, over time, they can weaken the glass. Is there any truth to this?
How would that occur?
Maybe the idea is that the reflected sunlight (heat) would damage the glass.
I can tell you that my 13-yr old Civic still has its original windshield. And for 9 of those years I used a reflective “sun shield” in it as it was parked at the office for 9 hours each day.
It sounds dubious to me.