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As someone who works in IT and supports 400 iPhones, the typical life span I am seeing over the last three years has been 12 to 24 months before they start having major problems and need to be replaced.
 
As someone who works in IT and supports 400 iPhones, the typical life span I am seeing over the last three years has been 12 to 24 months before they start having major problems and need to be replaced.

18-24 months, depending on the user.
 
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