It always surprises me how seemingly indestructible and simultaneously fragile phones are.

I've broken two phones in my life; both of them had on robust cases. The first time, I knocked my phone off of my desk at work. It fell three feet to the carpet and shattered the screen. The second time, I missed my pocket and dropped the phone 2-3 feet. Completely shattered the back glass and sent a hairline crack through the screen.

I've dropped my phones so many other times, in much worse ways (sometimes with no case), yet in these two instances they break. I'm almost at the point of not using cases, but I know my anecdotal experiences don't reflect reality.

The mechanics of a drop are complex. The phones are designed to distribute the forces and survive most falls, but there are ways that the phone can fall where it is very hard to prevent damage. Falls on the corners or edges tend to just scratch the case. Falls on the back or face tend to shatter the glass. That means that in 8 out of 10 basic fall scenarios the phone has a good chance of surviving. Of course with sufficient height and impact, the structure cannot diffuse the energy enough to avoid severe deformation and breakage. For face plants, just a tiny rock can focus the energy and crack a screen that might otherwise survive the fall.

External cases provide protection from scratches and scrapes in low energy falls. That is most of what I’ve experience so I put on a thin case for that. An external case can provide some cushion to dissipate some of the impact energy to reduce the change of deformation. That is where thicker is usually better. For me, that scenario is less likely so I don’t bother with thick cases.