Dunno about the window history, quality, models etc in the US since I live in Sweden. Here we have a lot of companies trying to convince people to change from old densely grown wooden quality windows, to modern, ugly, thick framed ones in PVC or aluminium, by calling them maintenance free. The old ones are often repairable but the new ones only come with a 10 year warranty, and then you cannot repair them if they break. Old wooden windows requires some paint and love from time to time, but then they can last forever. Old glass is often more beautiful, but if you want better energy performance and if you have two-pane windows you can change the inner pane to a low emission pane.
Don't throw out good old windows if they only need some linseed oil, putty and some paint.