I used my 13 Pro for 3 years caseless—honestly I wouldn’t do it again.
The screen was supremely scratched by the time I upgraded to the 16PM, and the stainless steel frame had a lot of nicks on it, especially on the corners.
Sure, if you’re super diligent and never set the phone down anywhere without wiping the surface down first, you’ll probably fare better—but I travel, I like the beach, and I don’t like treating things like they’re overly precious.
My 16PM is in the Apple Silicone case which I really like, and though I still don’t use a screen protector, the lip when placing the screen facedown has been beneficial.