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 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..