Very rare for me to open. Used cars, not a deciding factor on to buy or not. If they fail, they get closed and disabled. Weight up high, where you least want it. I would rather be without a "sunroof" in a rollover. Less headroom. More hardware, software and electrical components to fail. Drains to clean. I never want one when I buy new. But they seem to come in packages, like many other things some people do not want or need. That being said, three of my cars have them! All three were bought used.