Though I’m historically not a fan/user, I did get a (Spigen?) glass screen protector for my current 13 Pro. I was curious about their application jig which made the day-one, fresh from box installation, as promised, flawless. In use, the thin glass is effectively invisible and unnoticeable — even when used side-by-side with an unprotected phone.
I’ve replaced that screen protector once. I dropped the phone and it cracked. Of course, I can’t say whether or not the unprotected screen would have been damaged by the impact. Even so, given the lack of negatives and the peace of mind it provides when I reach into my phone pocket and pull out my keys…or a carbide scribe…I’ll likely repeat on my next phone — and my next iPad.
The sapphire lens protectors remain uncovered (and I damaged) though. Maintenance is usually a shirt wipe. Iso or ROR when called for.
Edit add: When I did remove the broken screen protector it left no trace of adhesive behind. I wiped the screen with a good quality optical cloth (mostly for good measure) and installed the replacement. No bubbles. No discoloration. No problem.