How Often Should Pool Screens Be Replaced?
No manufacturer publishes a service life in years
This was checked directly against manufacturer technical sheets for every major pool-cage mesh product, not inferred: Phifer, Saint-Gobain ADFORS and Super Screen all decline to publish a years-of-service figure for any product in this category. Warranty length is the only durability number any of them publish, and it is not the same thing as a lifespan.
What they do publish varies sharply by product. Super Screen's 17/14 and 20/20 mesh, and Phifer's SunTex 80/90 solar screen, each carry a published 10-year limited warranty. Phifer publishes no warranty duration at all for its standard 18x14 fiberglass, 20x20 No-See-Um, PetScreen or TuffScreen — not a shorter term, simply none published.
Two claims that show up in marketing and should not be treated as sourced: that fiberglass "becomes hard and brittle after 2 to 3 years" (a rival manufacturer's disparaging claim about a competitor's product, uncited), and that vinyl-coated mesh "will likely last 20-50 years" (an installer claim with no manufacturer backing). Neither appears on this site as fact.
The useful test instead of a number: push the middle of a panel with a flat palm. Mesh near the end of its life gives further than it should, does not spring back cleanly, and tears at the spline line rather than in the middle, because that is where it has been under constant tension.
Source: Phifer TuffScreen product page (no warranty published) — https://www.phifer.com/product/tuffscreen/
Source: Super Screen 20/20 No-See-Um, 10 Year Limited Warranty — https://super-screen.com/20-20-no-see-um-screen/
Source: Phifer SunTex 80, 10-year Exterior Sun Control warranty — https://screening.phifer.com/products/suntex-80
Not sure which of these is your problem?
Describe what you're seeing — a couple of photos helps — and I can usually tell you over the phone.