I'm kind of a noob when it comes to upgrading. I have never bought a new iPhone before and am wondering if I have to bring in all the phones I was to upgrade. Here's the situation everyone in my family wants in iPhone and we all have upgrades available. Can I go in and buy all the phones and just pop the sims in? Or do I need to have all their phones in hand? None of the current phones have micro sims if that changes anything. Thanks guys.