BLATANT PLUG. MODS PLEASE FEEL FREE TO DELETE IF INAPPROPIATE.
Husband and I own a security screen company.
Fibreglass mesh is fine. As you say fibreglass mesh has a "theoretical" lifespan of 10 years. In reality it is less than that in most situations. (dirt and dust, grease and grime and just general wear and tear).
Aluminium mesh is called for in certain brushfire areas as it is deemed to be higher protection against ember attack. lifespan would be similar to fibreglass.
The heavier PVC PetMesh would certainly last longer, but is not generally used on windows, but rather on doors against dogs, cats and toddlers
If you are looking at DIY.. We sell mesh either by the metre or the roll at www.restockdirect.com.au