Quick Answer: Battery life and storage are the most common reasons iPhone users tend to upgrade, but the new features are also a draw, and the Duo made waves this month. T-Mobile is offering up to $1,200 toward the cost of a new phone.

Apple unveiled their newest iPhone models at their “Surprise and shine” event earlier this month, including the long-anticipated iPhone Duo, the company’s first foldable model, which Apple describes as an “immersive canvas for everything users do.” But if your current phone is in decent condition, deciding whether to upgrade can be a conundrum. New devices can also be expensive if you’re paying the full sticker price.

T-Mobile is here to help. The carrier is offering up to $1,200 off the cost of the new iPhone 18 Pro models for anyone who trades in an eligible device or switches to certain coverage plans. That’s enough to cover the cost of an iPhone 18 Pro in full, letting you walk away without paying anything upfront. And if you opt for an older model from the iPhone lineup, T-Mobile will give you a credit on your monthly bills.

Here’s what to look for when deciding whether to upgrade.

When is the right time to upgrade your current iPhone?

CNET usually recommends upgrading your phone if it’s more than two generations old. But if you’re on the fence, here are some other considerations to think about.

Battery life

In a 2026 CNET poll, Apple users said battery life was the biggest reason they upgraded their phones. If your battery’s maximum capacity has dropped below 80%, it might be a good time to either replace it or opt for a new device. You can check its capacity by opening your phone’s Settings and selecting Battery, then Battery Health to see the current maximum capacity.

If you’re upgrading from an older generation of iPhone, the 18 Pro and Pro Max battery life, touting up to 45 hours of video playback off a single charge on the Pro Max model, is bound to impress. 

Storage capacity

Storage is another big reason consumers upgrade. If your phone doesn’t have enough storage space, it won’t even accept critical software updates from Apple, let alone let you download new apps. The iPhone 18 starts at 256GB storage, but can have as much as 2TB.

Better camera

The iPhone 18 functions more like a dedicated camera, letting you adjust the aperture to shoot in darker or lighter conditions. In Apple’s Photographic Styles, the 18 Pro also brings new options, including a way to add realistic film grain.

New iPhone 18 features and models

You’ve likely already heard about the iPhone Duo, the first foldable iPhone, which will be available for preorder starting Oct. 16. It’s designed to be better for consuming all kinds of media, with a 7.6-inch screen that can show 31 hours’ worth of videos on a single charge. For the iPhone 18 Pro and Pro Max, CNET’s reviewer also called out the new burgundy color, the slimmer Dynamic Island and the powerful A20 Pro chip.

But what if you can’t decide between the two form factors and want to have it both ways, using one phone for personal use, for example, and another for business? Thanks to T-Mobile’s new iPhone Handoff feature, you can use the same T-Mobile number on two compatible iPhone models, picking whichever phone best suits your needs at the moment, with all of your messages effortlessly syncing between both phones. 

How much better is the new iPhone 18 Pro than my older model?

Regardless of which iPhone you’re switching from, the 18 Pro will come with meaningful improvements. The camera is unmatched by any older model, and the battery life has become significantly better, even above the iPhone 17 (which also represented a big battery upgrade). The 18 Pro is also faster and sharper in its display.

Here’s a breakdown of the specifics.

Which new iPhone should I upgrade to?

The iPhone 18 Pro, Pro Max and Duo are all powerhouse devices, but a few key differences stand out.

The Pro and Pro Max feature the most impressive camera, with an aperture you can set to four different stops. The Duo’s camera is also excellent but does not have the variable aperture.

The Duo has both the smallest physical size (measuring just 4.64 inches tall and 3.31 inches across) and the largest screen, with a 7.6-inch screen in the interior. It can also be folded in numerous ways, and can stand on its own, so you can take video calls without holding up the device. The Pro and Pro Max have a more conventional smartphone shape.

Battery life is great on all three, but the Pro Max leads the pack, offering up to 45 hours’ worth of video playback. It’s followed closely by the Duo, which can play 44 hours’ worth of videos on its outer display and 31 hours on its larger inner display. The Pro, which can play 36 hours’ worth on a single charge, is no slouch either, and both the Pro and Pro Max are able to charge up to 50% in just 15 minutes using a 60W-capable USB-C power adapter, so even when you forget to juice up you’ll still be ready to go in no time. 

Should I get the iPhone 18 Pro or the iPhone 18 Pro Max?

Apart from battery life, the only meaningful hardware difference between the Pro and the Pro Max is their size. The Pro Max is half an inch taller than the Pro and slightly wider as well, with a 7.9-inch display (compared to the Pro’s 7.3-inch screen). It also weighs just over an ounce more. 

There’s also a difference in price: The Pro starts at $1,199 and the Pro Max at $1,299. However, with T-Mobile’s current promotion, you can get $1,200 off any model, whether you’re a longtime customer or a newcomer to the carrier, effectively transferring the cost of an upgrade from you to T-Mobile and allowing you to walk away with a Pro for free, or a Pro Max for just $99 upfront.

What pre-order deals does T-Mobile have for the iPhone 18?

The marquee offer here is T-Mobile’s $1,200 discount off a new iPhone. When preordering, you can get the discount either by trading in an eligible device (check the value of your current phone here) or by switching a line to T-Mobile’s Experience Beyond, Experience Beyond 2.0 or Go5G Next plans. Or if you’re shopping for a family plan and ready to transfer, you can stack this $1,200 discount with their Family Freedom plan for even better savings. 

If you prefer a different plan, you can still get a hefty discount from T-Mobile. The carrier is offering $930 off any iPhone 18 Pro or iPhone 17 model if you trade in an eligible device or switch a line to T-Mobile’s Experience More, Experience More 2.0 or Go5G Plus plans. And it will give you $730 off if you switch a line to the Essentials 2.0 plan or add a line and trade in an eligible device on most plans (including the more basic tiers).

Finally, T-Mobile is offering a $300 discount if you trade in an eligible device on the Essentials 2.0 or Essentials plans.

How do T-Mobile trade-in credits and monthly device financing work?

T-Mobile will immediately apply your trade-in credit to the purchase. Unless you’re buying the 18 Pro Max or the Duo, which becomes available for preorder next month, that means you won’t pay anything for your new iPhone upfront. 

If you still have credit leftover, T-Mobile will divide that amount by the number of months on your payment plan. For instance, say you have $400 worth of credit and you’re on a two-year plan. T-Mobile will divide that credit by 24, so you’ll see a $16.66 credit on every bill.

Upgrade your iPhone with T-Mobile

Once you’ve figured out which iPhone 18 model is right for you, all that’s left is to choose one of T-Mobile’s plans and bring your phone to a shop to trade it in. But it’s better not to delay, because the trade-in value of older phones is often highest around the time that new models are being released. As the months go on, the value of older iPhones will depreciate.

Click here to learn more about T-Mobile’s upgrade offerings for new iPhone models.

FAQ

When should I replace my old iPhone instead of keeping it?

It is generally time to upgrade when your device’s maximum battery capacity falls below 80%, trade-in value begins to drop steeply or the hardware no longer supports the latest iOS updates.

How does the T-Mobile iPhone 18 launch offer work?

Get a $1,200 credit, equivalent to the cost of an iPhone 18 Pro, when you trade in an eligible device or switch to one of T-Mobile’s premium plans.

Can I get the new iPhone 18 Pro or Pro Max for free from T-Mobile?

The carrier is offering up to $1,200 in credits for customers who trade in an eligible device or switch a line to the Experience Beyond, Experience Beyond 2.0 or Go5G Next plans. With a credit that large, you can walk away with 18 Pro with no upfront cost, or get a Pro Max for just $99. This offer won’t last forever, though, so act fast if you want a phone upgrade on T-Mobile. 

Do I need to pay anything upfront when upgrading through T-Mobile?

No — T-Mobile has financing options that allow you to pay $0 upfront. With its EIP Flex 36 financing option, you can get a new phone without even putting up money for taxes, depending on offer eligibility. If you qualify, the plan allows you to stretch out the expenses (including the cost of the device, taxes and activation fees) across three years’ worth of payments.

How are trade-in promotional credits applied to my monthly account?

T-Mobile will divide the amount of credit on your account by the number of months in your plan. So if you have $400 credit and a two-year plan, for example, the carrier will shave $16.66 off your bill every month.

Will my trade-in value change if my old phone has minor wear and tear?

If the damage is minimal, the trade-in value won’t be affected. As long as it turns on, the screen isn’t cracked or chipped and there’s no liquid damage, you’ll receive the full amount.