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When I bought my wife a new phone she used to get upset saying how she had her phone exactly how she wanted it and does not want a new one, so I bought myself the upgrades and shes fine with whatever she has now. When we switched from sprint to VZW I upgraded her from the 4 to the 4s because she used to get upset that mine had Siri and hers didn't.
 
My wife has the 4s and I have the 4. She's going to get the 5 and I'll get her old 4s. She's always on her phone, so she'll get more use out of the new one.
 
My mother only uses her iPhone 4 for texting and occasional surfing/ streaming. I don't think her experience would change much with an upgrade, so I just hand down my old phones to her. Devices mean different things to different people, and that's just dictated by how they are used.
 
I'm handing down my IP4S to my husband AND using his upgrade to get a new iPhone. He's not interested in an iphone5 and knows how much I enjoy new technology.

He's currently using my old 4, and was using my old 3GS before that.

Same here although I did let him get his iP4 new because he was using my first generation iPhone before that.
 
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