The average American is now hanging on to their cell phone nearly three years, according to new data from Chetan Sharma Consulting. That's up from about a two-year upgrade cycle in 2014.

The big culprits: The end of two-year contracts and a maturing cell phone market have been the key factors.

"Consumers are treating phone purchase akin to a computer buy and given that there are only minor hardware changes from model to model [with exceptions], there is less incentive for consumers to upgrade," CEO Chetan Sharma told Axios.

The X factor: Sharma says the arrival of the iPhone X could lead upgrade cycle times to shorten in the coming quarters.