Nope, I run naked. For some reason I took the seidio case off my old HTC EVO years ago and realized that my phone wasn't nearly as bulky and annoying as I thought it was.
Now I run a moto x with no case or screen protector and it's holding up just fine even after a dozen or so drops in the past year.
Now I run a moto x with no case or screen protector and it's holding up just fine even after a dozen or so drops in the past year.