Fiberglass is 8x stronger, matches glass expansion rates (eliminating seal failures), and can be painted. It costs more but lasts significantly longer with zero maintenance.
40–50+ years. The frame material doesn't warp, rot, or lose structural integrity. The matching expansion rate means glass seals last far longer than in vinyl or aluminum frames.
For homes that plan to stay in the family, yes. The 40+ year lifespan and zero-maintenance frame make fiberglass the lowest cost-per-year window option available.