I am not going to quote above thread, getting too big. Now it is either S9 or nothing. Come July all of my S7s will not be almost worthless, once they are retired I would still be able to run my S9, 1 S9 will replace 3 S7s but still consume as much as 1 S7 and continue to contribute to the network. I pay 300x or 400x times more than it costs to make for an iPhone, I don't see it any differently.
Really what this comes down to is that there's multiple ways to justify mining. I originally approached this as a hobby. After playing with Scrypt for fun (not caring about losing money) I used the BTC-in-BTC-out discipline and that worked well for me. I profited in BTC terms with every miner.
Then the S7 came out and I threw that discipline out the window. It was fun to have the latest hardware, but the fact that I could never get the BTC out that I put in bothered me. I ended up selling my S7s early to recoup fiat ROI.
On top of all this was the S7 B1 delivery delays, and corresponding compensation delays, because Bitmain planned badly. Instead of getting my units on time, they missed the shipping deadline and my S7s stayed in their data center hashing for them instead of me while the whole country was getting plastered for a week long festival.
All of this added up to me feeling like an idiot for stepping away from my discipline and yielding all control to Bitmain.
As much as I love the hobby and as much as I miss actively mining (it's addicting), this time with the S9s I'm not buying until it makes sense in BTC investment terms. If that never happens, I'll stick with old miners. Depending on the timing, maybe when you're ready to sell your S7s I'll buy them back from you
Again, this is my preference, not an argument for how everyone should make the decision to buy or not.