For an older daily driver, is buying a junkyard windshield a good idea? I would hate to swap in a used windshield and then see it delaminate. SO, how old of a windshield would you swap into a car?

I guess it makes sense if your replacement is expensive and the JY part is good.
On my daily cars, which I keep in good enough condition that they actually get compliments, I just buy new ones.
Those rigs have 205,000 & 286,000 miles, and have both been great vehicles.
Stone chips & such seem to merit a replacement maybe every 8-10 years for me, I guess.
Usually based on looking into the sun and the glass not being clear, unless one really takes a hit & cracks.

My 51 still has it's original windshield and it;s still good.

But I can buy a new one for pretty reasonable a price since it's flat.

Old windshields tend to get scratches, surface imperfections, chips, and cracks before they de-laminate. They get hard to look through in bright sunlight or at night with car headlights approaching, you long before they separate. If the glass is clear, it should last a long time.
I run a lot of 30s, 40s & 50s stuff, If new glass is available and isn't really expensive, I wouldn't even consider putting in used glass, especially a used windshield. Gene

I would think a replacement might be, or id hope might be better tech and break a bit different for the good when the air bags in ones hellcat 70 cuda dont deploy.

Age doesn't matter - if it's still in good condition now.

Salvage yard glass can be awesome, just bring a squeegee, water/windex and papertowels, something to clean them to check first.
Delaminating you can see almost immediately, so that's easy.
Then check for pitting and scratches after a thorough cleaning.

There was a time when we had no kids, I spent lots of time in salvage yards.
The glass I found here that were the best, were in old tree-covered yards, where the car was sitting for decades.
- Art

I agree, I got 490K on my PU, and currently in the process of deciding whether its worth installing the third new windshield from all the tiny chips, that mainly effect night driving. My semi windshield though has fogged up around the edges maybe three times over the years, with under 20K miles, and has to be replaced because of DOT regulations every time

I haven't seen a lot of delamiination issues enough to be concerned..

I fully agree with some of the above positive comments.

I worked for a couple of auto glass distributors back in 1978-79 & windshields (which are laminated) we built even better back then as far as I'm concerned - they were a bit thicker glass than today's windshields. If you find a good used windshield & it is not de-laminating, then it will not start. The plastic they use to laminate the two sheets of glass together is tough as nails & stays clear. Just don't chip any of the edges of the glass - removing a windshield from a vehicle has to be done very carefully - do it slow & careful.

On an interesting note, the first distributor I worked for had all kinds of brands of glass - PPG, Carlite, LOF, Mopar, etc. We had a Mopar clear Superbird back glass in stock - in the cardboard wrapper. I could have probably bought it for $70.00 & really wanted to, but $70.00 was way more than I could afford back then. Those were the days.

My 03 dually has 282K on it and is definitely in need of a new one...

Never a mark big enough to cause a crack but 1,000 little marks everywhere is making it a lot harder to see when driving into the sun...

I've never had an issue reusing old glass as long as it is good shape...