How many years of life have the iPhone and other Apple products?

There is talk of three years for an iPhone and an Apple Watch, four years for Mac and Apple TV.

In an FAQ published on the company’s website this week, Apple addresses several questions about its relationship with the environment, a topic which Tim Cook and the other executives are very passionate about.

The second question posed in the FAQ is: “How does Apple conduct its Product Greenhouse Gas Life Cycle Assessment?” This portion of the is what caught the eye of several publications around the web on Friday:

“To model customer use, we measure the power consumed by a product while it is running in a simulated scenario. Daily usage patterns are specific to each product and are a mixture of actual and modeled customer use data. Years of use, which are based on first owners, are assumed to be four years for OS X and tvOS devices and three years for iOS and watchOS devices.”

Apple then, an iPhone 6 will be an excellent product until 2018, after which it may always be sold to another person less interested in the power of the hardware or recycle it.