By keeping your iPhone in mint condition, does this leave some sort of room to sell it and buy the newest phone out there when the time comes? I know simply resale just means when you feel like selling it, you can for high as it is in mint condition provided you used a case... But are there any obstacles keeping your from just turning around your previous gen phone to have some money towards a new model? I really want to know, because for some reason I have a feeling 2 year contract means only with the phone you currently have, for ex iPhone 3gs...