I've had the iPhone 3GS, iPhone 4S, iPhone 5S, iPhone 6S, iPhone 8, and now an iPhone XS.
My iPhone 3GS's display somehow got a scratch. I've been using screen protectors ever since (anti-glare/matte, which not only protect the screen, they improves visibility and how it feels to touch).
My iPhone 3GS also had a crack in its body. I've been using a case, ever since.
That's about it. With a case (even basic or cheap ones) and a cheap screen protector (about $2 each), I've (almost) NEVER had to worry about an ugly or damaged phone. No cracked or shattered glass. No scuffs or scratches on the body.
If you're worried about damaging your $650-$1550 iPhone, then an investment of just $10-$60 for a screen protector and case can prevent it from breaking and improve its usability.
Besides the issues I had in 2009 with my naked iPhone 3GS, I actually had a boo-boo with my iPhone 8 just a week ago. I dropped it and it got a small ding in its metal at the bottom. I was using the official Apple Leather case. While they can keep the phone safe in many drops, the bottom of the phone is exposed, and the "open" case won't help at all if something hits just right at the bottom. My iPhone 8 is the black one, so a hit against its metal gave it a shiny dent. A minor issue, but it will still cost $99+tax to fix.
(Despite always using a case & screen protector, I still get AppleCare+. I've mostly used it in the past to cover liquid damage.)