Ya' know, I've always kind of wondered about windshields. I have a '72
Merz with around 155K miles on it, and the original windscreen, and
it's fine. My mother had a '90 300D 2.5 and my father a '91 350SDL, and
they put about the same mileage on them over the years, but the 300D
2.5 had its windshield become virtually opaque from sand damage at 100K
miles, and the '91 still has its original windscreen at 172K miles.
Figureing that it has the same glass in it, I sort of developed this
little theory, which is utterly baseless, that the more swept back the
windscreen is, the more likely it is to get hit by grains of sand at
high speed whereas a more up and down windscreen has a buffer of air in
front of it that slows sand before it hits the windscreen. Then again,
maybe my mother just drove like a bat out of hell.

Not my experience.  My 2002 has had 2-3 pits/stars repaired and, just
recently, we had to replace the windshield.  We drive the same routes,
more or less, for years and other vehicles have not suffered so.  (Of
course, they had other problems.)

Kal

Anything that abrades away pockmarks and scratched would be an abarasive,
not a wax.

Cerium oxide is what you use to remove scratches in glass. it's a LOT of work.

If you get the windshield wet you'll notice it looks brand new as the
water fills in the tiny holes.

Anything that will do permanently what water does temporarily what water does
would "fix" this problem but I reckon the lack of a commercial product that
deos this means nothing is a practical material.

When they repair cracks they use an epoxy. In theory you could do the entire
windshield but you'd need to polish it and it will get scuffec very very easily.

The last time I needed a 126 windshiled I paid $250 installed a couple of years ago
for a new one. Shop around, in person, explain you'll pay cash and find a bargin. That's
the way to get the clearest windshield for the least money.