My mother cracked the glass screen protector on her iPhone. She knew that she has the same model I do, and called to see if I had a spare screensaver I could rush over.
Then she expected me to put it on the phone. Woe would fall upon me for each bubble I left in the screen, thankfully these guys are easy to put on.
These Ailun protectors are cheap and seem to de-bubble quickly if the screen is cleaned well first.