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