Your screens are probably not gray in color. Most often times screens are made from a thin vinyl-coated fiberglass. These screens are very common, even now when you purchase new windows. Fiberglass screens only have a lifetime of 4-8 years depending on the UV and elemental exposure.

UV rays eventually breakdown the thin vinyl coating leaving the glass core vulnerable and exposed which then becomes brittle, turns gray or powdery, and tears easily.  Yes, the fiberglass screens are much more affordable, however you’ll be replacing them more often. Where as vinyl screens can last 10-15+ years!