iPhone 6. I should have known. The moment after I said we'd be restarting Ask iMore we got flooded with questions, and roughly half of them were variations on — What's the iPhone 6 release date? Should I buy the iPhone 5s now or wait for the iPhone 6? It's amazing that Apple manages to maintain such a high level of interest in the iPhone line even as it approaches the mid-point in its annual product cycle. It's also perfectly reasonable that people considering big electronics purchases — or contract extensions — want to make informed decisions. It's challenging to come up with an answer that both satisfies people's genuine curiosity, reasonably sets their expectations, but also points out Apple hasn't announced anything and likely won't for months and months to come. However, if you're not adverse to playing the odds, there is an answer I can give you now...
Apple announced the iPhone 5s on September 10, 2013 and released it on September 20, 2013. Apple announced the iPhone 5 on September 12, 2012 and released it on September 21, 2012. If Apple sticks to that pattern — big if — they'll announce the iPhone 6 on or around September 9 or 10, 2014, and set the release date for September 19, 2014.
Of course, Apple doesn't always stick to patterns. The iPhone 4s was announced on October 4, 2011 and released on October 14, 2011. The iPhone 4 was announced on June 7, 2010 and released on June 24, 2010. Hell, Apple announced and released the iPad 4 only six months after the iPad 3. Apple can always push back a production schedule if some hardware, software, or services component won't be ready in time, and they can always move it up simply to break patterns. So, it's a gamble. It's basically playing iPhone 6 release date roulette.
Here's the standard Mobile Nations advice — if you need a new iPhone now, today, get the iPhone 5s. If you don't need a new iPhone, now, today, wait as long as you can and then get whatever the best iPhone is when you do need it. After all, there will always be something better on the horizon.
However, if it's less about need and more about want, then you can always buy an iPhone 5s now, keep it in great condition, and then sell it when the iPhone 6 comes around. iPhones hold their value remarkably well, and we have a ton of readers who make sure they buy the new iPhone every year by selling their old iPhone.
It takes some work, and assumes some risk, and it's certainly not for everyone, but if you really want to have and iPhone 5s and an iPhone 6, it's something to consider.