Stay or Fold

For a long time I bought the new smartphone that launched each fall. From 2014 to the early 2020s, every new phone brought a step-function improvement in size, build quality, and camera quality.

But as the hardware improvements became more incremental and prices climbed past $1,000, I started asking whether I really needed the latest phone every year. If a new phone didn’t meaningfully improve the jobs I cared about, I kept my current one.

The iPhone Duo makes this decision framework harder. It may be worse at some of the jobs I value while enabling new ones I have not considered.

Three jobs

A phone can do almost anything, but there are three things I rely on mine to do consistently:

1. The phone must be pocketable. It fits in my pocket without bulging out.
2. The phone must last multiple days. I charge overnight, but on the nights I miss a top-off, I don’t want a dead phone at 8 a.m.
3. The phone must have a best-in-class camera for its size. I want to catch the moment via photo or video. This matters more with young kids, where the moment is over in seconds. Yes, a DSLR takes better pictures, but the phone camera is the camera I will always have with me and is often my go-to.

A new phone has to preserve these baseline jobs before additional capabilities start to matter.

The iPhone Duo puts pressure on all three. Pocketability comes down to reducing X-Y dimensions without growing thickness too much. When folded, the Duo is notably thicker than a regular slab phone (11.3mm vs 8.75mm), which is a pocketability risk.

Open, the Duo is only 5.2mm thick. But this can create reduced space for both the battery and camera. Reduced camera volume can force compromises in sensor size, optics, or camera count, risking poorer photo and video quality than a comparable slab phone.

More screen real estate costs battery

Increased screen area has an obvious benefit. I can draft email while referencing a document. Or I can take notes in real time while viewing content in a browser.

One use case is relevant for me: ForeFlight. ForeFlight provides aviation charts and other information relevant while flying. I fly piston-engine planes and a larger screen on my phone means less pinching/dragging and more information viewable at a glance without carrying a separate tablet.

However, every one of those wins happens with the phone open, bright, and driving a larger display. The features pay out in exactly the mode that drains the battery fastest. So the reason to own one and the cost of owning one are the same event.

The case against me

If I stop here, the answer is simple: buy the iPhone 18 Pro (or even keep my current Pro phone). But new form factors create new behaviors, and those behaviors are difficult to value before using the product.

Before the iPhone, smartphones were designed around physical keyboards and fixed controls. Replacing those with a touchscreen turned the front of the phone into a programmable interface. Controls could change depending on the task.

The first-order benefit was more usable screen. The more important second-order effect was that software could reshape the device around the job. That enabled behaviors and app categories users were not asking for before the capability existed (e.g., maps with gestures, games with custom controls).

For an iterative product, my existing jobs are a pretty good evaluation framework. But a step-function change in hardware requires consideration of emergent jobs enabled by capabilities I have not lived with before.

The problem is that I can measure support for my existing jobs before buying the product. I may need to live with the device a bit before I can identify and evaluate emergent jobs.

Emergent jobs

So what will these new supported use cases be? Displaying apps side by side is table stakes, and a slab phone already does it, worse. Apple did announce new features unique to the Duo vs. its Pro phones: Duo Preview, Smart Take, and Kid Cue. These are new capabilities but not automatically a valuable job.

The harder question is if these and other features change recurring behavior. If these features end up being something I use a few times a month, it does not pay for a cost I take every day.

Where I go from here

With Apple’s announcement, I already know:

1. Folded, the Duo is 117.8 x 84.1 x 11.3mm. The iPhone 18 Pro is 150 x 71.9 x 8.75mm. The larger width and thickness make me suspect a pocketability trade-off, but until I physically try it I can’t confirm.
2. Duo is rated for 31-44 hours of video playback (depending on the mix of outer vs inner display) whereas the iPhone 18 Pro is rated for 36 hours. The more I use the large screen, the higher the chance I will see worse battery life than the Pro phone.
3. The Duo has no dedicated telephoto camera and no variable aperture, both of which help with scene and light capture.

I don’t yet know whether the software Apple is putting out with the Duo will change my recurring behavior. So maybe the real question isn’t “does the Duo support my core needs?” It’s “should I spend the extra $800 and trade photo quality to find out if the Duo creates a job I don’t yet know I have?”