The glass in your bird is looking a little milky, there’s some crazing on the windshield and a little crack where the pebble hit. Is it time to replace the windows? How can you tell? What’s it going to cost? How can I make the glass last longer?
First, it’s worth noting that what’s on your airplane probably isn’t glass, it’s acrylic (but, rather than constantly saying “windshield and windows,” we’ll use “glass” as a shorthand term). Acrylic doesn’t last forever, it scratches and discolors, and its longevity depends partially on how you treat it.