Most years, it's not very hard to decide which iPhone model to buy. I always go with a Pro model -- usually the smaller of the two. But with next year's iPhone 17 line and the expected ultra-thin 17 Air model, my purchase decision will be harder than ever. Here are the key factors I'm considering.

Apple continues experimenting with its flagship iPhone lineup, particularly with its fluctuating fourth model.

There used to be an iPhone mini, but it didn't sell well enough and Apple replaced it with the iPhone Plus. Turns out, history's repeating itself and the Plus hasn't justified its existence either.

Next year, Apple instead plans to ship the iPhone 17 Air. Highlights include:

On paper, the 17 Air won't be the 'best' iPhone, but it will offer a taste of the future.

Sort of like how the iPhone X represented a leap forward in industrial design -- but this time, with some compromises that make it less compelling.

There's a lot about the iPhone 17 Air that sounds great to me. After years of iPhone updates that have done little to change the physical design of the device, a major form factor change is exciting.

Right now I use an iPhone 16 Pro. And typically I would expect to buy a 17 Pro next year.

But the 17 Air may change that. There are three key details that will make the decision especially hard:

It would be hard to give up so much for a new iPhone model, but we'll have to wait for Apple's full lineup unveiling to make the most informed decision. So far, we know a lot about the 17 Air but very little about the 17 Pro and Pro Max.

I'm inclined to think I'll still buy the 17 Air despite the sacrifices that model entails. But if the 17 Pro gets some killer updates that are Pro-exclusive?

Apple could make the decision even more painful.

Which iPhone 17 model do you plan to buy? What are your key decision factors? Let us know in the comments.