I've had my Nexus 4 for over a week now, fully NAKED. I've ridden all over NYC on a bike with it daily in my jacket pocket. If it's not in my hands or pocket it's resting on a flat surface charging and I have yet to get a single scuff, nick, dent or scratch thus far.
I baby my devices and have never had a cracked, scratched or otherwise non-mint-condition screen even after years of use... So I really wonder about some of these fat fingered, careless folk that think if they drop or otherwise abuse their devices why it SHOULDN'T break, lol.
If you've got sweaty palms, are careless, haphazard or otherwise not extremely careful with your devices you need to buy a suitable CASE & SCREEN PROTECTOR INCLUDING A BACK SCREEN PROTECTOR if the case doesn't protect the whole back.
It's that simple. If you don't, you're taking a huge gamble & have no one else to blame for your device breaking but you.
Sent from my Nexus 4