Well this morning my Iphone 4 started acting odd after 8 months of perfect performance. I could not hear callers unless I had the speaker on or the earphones plugged in. Did the usual tricks the the earphone jack - no good. Did a complete restore as a new phone - on the advice of Apples telephone support - no good. Got a Genius appointment and after a careful look for signs of water (it's never been wet) they exchanged it for a new one - a refurb I am certain. Works great - wonderful service.