Well, my wife doesn't care WHAT phone we buy when we upgrade. She lets me handle that and the service. However, her one stipulation is that WHEN I do buy she gets the same device I do - unless she has some specific preference. This way it's not just me upgrading and leaving her behind because she doesn't really do tech.
2012 was an odd year because she decided that her portion of our tax refund would go instead to a backyard swing set for our kids. So she was on her old Touch Pro for an extra year longer than me. But I upgraded her to the 5 in 2013. We always buy the max capacity Apple offers so the only difference between her 64GB iPhone 5 and mine is color.
Last year I upgraded and got the 128GB 6+. She didn't want the larger phone so she got the 6. When we ported to T-Mobile I got the 6s+ and she again did not want the larger phone so she got the 6s. Both phones, 128GB. She had gold for the 6 and rose gold for the 6s. I stay with Space Gray.
Next year when we upgrade she has made her preference known that she now wants the larger phone. So it'll be two 256GB models of whatever the larger model it is Apple will be selling. Our only difference then will be color.
In my son's case I was looking for an 8GB iPhone 4s. His is white, but color at the time was irrelevant to me. A friend had a 8GB 4s for $20. Just happened to be white so that's what my son got.
But yeah, we generally stick to Apple products. There are two iPad Air 2s in the house as well as PowerMacs and PowerBooks. Only one Intel Mac, 2006 era.
That's how we work it anyway.