Really depends on what you're trying to keep out. A standard mesh might work fine, but if you have small insects, you might need the finer "no-see-um" mesh.

If there is any chance dogs or cats might claw at it, there are pet-resistant screens to.

On the flip side, from the aesthetic point of view...some screen obscure visibility more than others.

It's really a matter of defining what you need then find the screen to fit those needs.