Window screens have come a long way in a few years. In addition to keeping insects out and letting air in, they can now protect you and your possessions from sun damage. Here's an overview of what's available.
Replacing a damaged section or an entire screen can be done with tools usually found around the home and by handywomen and men alike.
Even the highest quality screen available will deteriorate over time. When it eventually becomes necessary to replace or repair window screens, call a professional with the tools and experience to do the job properly.