All things break down with time and sun exposure. That said, the vinyl window of the 80's are long since dead. We have nearly 20 year old installations that I have come back to for other projects, that look fantastic and work flawlessly.

In the high performance world (i.e. U-Factor and Air Infiltration), the vast majority of your good windows are going to be either vinyl or a composite product.

+1, depends on quality. I too see good quality vinyl windows at 20+ years old that look brand new, where other low end products are ready for the landfill by year 10.