No, it shouldn't break that fast. Not without some other circumstances going on. The rust would concern me...it shouldn't rust out that fast. Did anything really noteworthy happen in/around your garage in that time frame? Rain Damage or some other kind of leaking?
I may be wrong, but the NFRC (The National Fenestration Rating Council) has a website that does ratings for stuff like this. Don't remember the URL, but I seem to remember them actually rating windows by manufacturer.
Not sure if there is a good way to directly measure.