In years past, Apple has always waited two years before redesigning the iPhone, but this year they broke the trend. Aside from a few minor changes, the overall design and style of the iPhone 7 models is the same as last year's iPhone 6s models, and the iPhone 6 ones before that, so it's almost as though they've switched to a three-year cycle—just as early reports suggested.
The familiar look has many Apple fans a bit crestfallen, knowing that they won't be getting a visually-updated iPhone this year. But, aside from aesthetics, some very minor changes have ensured that Apple's latest smartphone is doubly disappointing from a design perspective.
The main advantage of two-year design cycles is that accessories like cases and screen protectors will fit both generations of iPhones perfectly. Ultimately, this means there has always been a wide array of accessories available at every "s" launch, as the same exact measurements carried over from last year's model.
Apple even took this principle a step further with their iPhone SE release in March of this year, as one of their main selling points was that the new, smaller iPhone would be fully compatible with old iPhone 5 accessories.
The iPhone 7 models look almost identical to their predecessors, and the dimensions are exactly the same as with the iPhone 6s models. But now that Apple has added stereo speakers, one set on the top and one on the bottom of the device, so virtually every case made for the iPhone 6 and 6s models won't work because the top speaker will be covered.
Even if you somehow managed to retrofit an old case, there would be a big hole where the headphone jack used to be, and the new microphone and speaker layout would be covered up partially.
While the iPhone 7 is identical in terms of looks and measurements to the iPhone 6 and 6s, the iPhone 7 Plus has a new dual-lens camera, which means the opening for the camera and flash will be bigger. That means there's zero chance of reusing and old iPhone 6 or 6 Plus case.
Old screen protectors should work fine on the iPhone 7 models, but custom skins may only work on the iPhone 7, not the iPhone 7 Plus, because of the dual-lens camera.
Then, of course, your headphones won't even plug into the iPhone 7 without an adapter, as Apple made the shift to Lightning headphones. They are including Lightning EarPods and a mini jack-to-Lightning adapter with the iPhone 7 models, so at least you'll be set if you already have a set of headphones you love.
So before you pitch a tent in front of your local Apple Store this year, make sure you have room for the truckload of new accessories you'll need to buy. On the bright side, this underwhelming release should at least result in shorter lines.