But most of us don't need a new phone, of course, and lots of our iPhones will probably last at least a few years, especially if you're willing to replace the glued-down battery, which has a limited lifespan. But on this iPhone Day, it's worth considering how long Apple expects an iPhone to last. When it released its iPhone 7 Environmental Report a year ago, Apple wrote that it "conservatively assumes a three-year period for power use by first owners," which is "based on historical customer use data for similar products."

As Apple readies its annual reminder that the expensive smartphone in our pocket is now obsolete, you are, no doubt, wondering if it's time for a new iPhone. The yearly refresh and the iPhone Upgrade Program have conditioned us to want to get a new device every single year.

Greg Joswiak, Apple's VP of iOS, iPad, and iPhone Marketing, told Buzzfeed last month that iPhones are "the highest quality and most durable devices. We do this because it's better for the customer, for the iPhone, and for the planet."

But in court, Apple argues that it is only responsible for ensuring the iPhone lasts one year, the default warranty you get when you buy an iPhone. For comparison, if you enroll in Apple's iPhone Upgrade Program, you will be paying for your new phone for two full years.

We know this because Apple is currently fighting a class-action lawsuit over the widespread premature failure of tens of thousands of iPhone 6 and iPhone 6 Plus devices due to a design flaw that's become known as "touch disease." In that court case, currently being litigated in California, the plaintiffs attempted to argue that "consumers reasonably expect that smartphones will remain operable for at least two years when not subject to abuse or neglect because the overwhelming majority of smartphone users are required to sign service contracts with cellular carriers for two year periods."

Apple's motion to dismiss in that case noted that the plaintiffs' phones broke more than a year after they were purchased, which is after the warranty expired. If your phone breaks after the warranty is up, well, you're out of luck, Apple argues.

Arturo González, the lawyer representing Apple in the case, wrote in the motion—filed in April and embedded below—that it is "not appropriate for courts to rewrite the express terms of a warranty simply because of a consumer's unilateral expectations about a product."

"Nowhere do plaintiffs allege that the iPhone 6 or 6 Plus deviated from Apple's intended design"