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I've always used my phones without a case.

It looks, feels, and fits much better in the pocket. I think a case makes the iPhone look much less elegant and bulky. I'm one of those who thinks the phone looks better with some visible signs of wear and tear.
 
I've tried my 5C w/ and without a case and it always feels better without. As someone stated earlier it's easy to put it in your pocket w/o a case.
 
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