In the span of a VERY short time I will have replaced my iPhone 4 two times for two separate hardware related issues. Return #1: My phone kept messaging "Sim Not Inserted" for hours at a time. Apple Store tested it, deemed it a hardware issue, then replaced it. Return #2: My phone's headphone jack no longer works properly. The headphone plug is inserted with no friction and needs to be finely twisted into just the right place to produce sound out of the headphones. Apple Store manager tested it, deemed it a hardware failure, offered to return and replace BUT...no new phones available yet. How long should I keep up this return/replace cycle before going back to my old iPhone or buying another device? I DO love the iPhone 4 and I very much want it to just work. Spending too much time in the Apple Store... Usually a cool thing, but now it's just getting frustrating. Thanks!