I've owned a number of Macs purchased new. Starting in 2005, every two or three years I would buy a new Mac. In my case, Mac Mini or MacBook. It was never the best, usually it was the lowest model, and I spent a little extra money to upgrade it to max ram or a bigger harddrive on my own to save money. I also always did my research so that I knew what I had would last me a few years.
My refresh cycle has gotten longer and longer and longer, however. In 2005, I bought an Mac Mini G4. In 2008, I bought a MacBook white. In early 2011, I bought a 13" 2010 MacBook Pro. That lasted me until March of 2015, when I purchased a 13" 2012 MacBook Pro, still my daily driver. In fact, it still has Apple Care (and thank goodness for it, I'm on my second battery and my third magsafe adaptor, and I still have Apple Care until March 2018). I have taken extremely good care of it, and it's in near perfect condition, save for my A and my E keys which are worn from use. I have really strong nails, and I usually destroy E keys very quickly, even when I try to keep them cut. But it's a minor thing to replace them.
Of course, I have owned a wide variety of used and rescued systems (like G4 Towers, a second Mac Mini, and my current Mac Pro 3,1, but those are not my primary machines).
You'd expect that in 2018, I would replace the 13" 2012 MacBook Pro according to my previous refresh cycle. So a new MacBook Pro something or other, except...
1) The MacBook Pro 13" 2012 is still a capable machine: Honestly, while the CPU and RAM are maxed out (it's the Intel dual-core Ivy Bridge i5 with 16GB of RAM), and works very well already, my next step is going to be to toss in a second Samsung 250GB 850 EVO SSD in Raid 0.
2) I want to be able to change parts out: Frankly, that can't be done on recent MacBook Pros, so my plan is to actually go from the 13" 2012 to a 17" Late 2011, and put my 16GBs of RAM and my Raid 0 SSDs in it. I will then sell the 13" 2012 in some kind of configuration.
I'm not doing anything with Apple desktops until I'm done updating my 2008 Mac Pro.
Not only is my iPhone 6S still perfectly fine for me, I'm also jailbroken on iOS 9 and have kept it there for specific reasons. I see no reason to get a new phone at this time, and if I do get a new phone, given my specific feature demands, I may finally switch to an Android phone.
At this time, I probably don't need or want an iPad. I was one of the first in line for the iPad 1 in 2010, and I only sold it very recently. Given the great disparity between the most recent iPads and the iPad 1, I am sure I can get a "wow, this seems really fast" feeling from an older iPad.
Honestly, at this point, have we reached a stage where there's no real strong reason for a prosumer like me, who does a little bit of everything, but nothing to a professional standard, to purchase a new product from Apple? My feeling is we have. And given the seemingly limited nature of future "proofing" the current systems, there's not even anything I feel I really want.