Honestly, this comes down to learning how to handle your phone. It's a lived practice, a conscious effort to handle your phone without error. And handling it properly will go so much further than any screen protector or case ever will.
Make sure the phone is sliding in your pocket and not outside of it as you slip it in. Make sure you have it firmly grasped if you are walking with it. Never try and hold something else in the hand you hold your phone in. If you visit the beach, or were just visiting, make sure you either have a screen protector for scratches, or make sure you clean your hands and pockets before continuing to carry/use your phone. Avoid placing your phone on uneven surfaces or areas that may have other things placed on top of them. As you get out of the car, make sure you hold your phone within your pocket while exiting. Make sure that your pants/shorts don't have pockets that are angled in a way your phone could fall out.
There are so many more things that I keep consciously in my head as I interact with my phone that allows me to never have dropped or damaged my phones. This is why I typically do not use a case (although I use a minimal case on my S7 Edge solely for less accidental touches). Never has one on my G3 for two years. Never on the phones before it.