Carriers and mobile retailers have created their own dilemma by signing up users for two year contracts. This means that retailers won't get another shot at their next iPhone for 23 months or more. Given the rapid pace of innovation, many users are either left out or finding creative ways to upgrade. Personally, I leverage our Family Plan so I can get the latest iPhone each year and hand down my one year old model to a family member.
AT&T has their "Next" plan which allows customers to basically pay over time for the privilege of upgrading frequently. I just received an email from Radio Shack encouraging me to take advantage of that plan, and upgrade now. Indeed, they are promoting a Samsung Android phone, in the email, feeding off the iPhone user base who has been waiting for a larger screen.
Given how close we are to the next iPhone, with at least a 4.7-inch screen, I'm not taking the bait, but it might be a good way for some users to get their next phone, whichever one they want!