Pika: Yes, I really want to buy next year's iPhone (and almost certainly will) -- it was just a question of: should I buy an SE or 7 now to tide myself over until then. My 5s is perfectly adequate, but I would much prefer something right now with a better camera and battery life. I think my decision came down to: if owning the SE for a year will be that much cheaper than owning a 7 for the year, I'll be fine to get the SE.
Calculate it.
$450 SE
Within a year - $300? (minus $150)
$650
Within a year - $400? (minus $250)
You have to also think like a second hand buyer. I sell multiple iPhones off Craigslist in the States and OLX in the Philippines. I don't do eBay. Too much taxes and I don't even have a PayPal account. I prefer face to face interactions which can be fun and help improve your personality and sales skills. I was surprised I was able to sell a three-year old iPhone 5 last year for $200 and it wasn't even in mint condition. Maybe 7.5/10 condition.
But the sweet spot for buying a year old iPhone or any other flagship is nothing more than $400. This includes Plus models. So for people being able to sell it after a year for $500, good for you. Where are those suckers? This is why flagships are so overpriced because how quickly they drop in price after a year. It's like buying an expensive car. The moment you drive it out of the lot, goodbye resell value. Plummets in half.
An HTC One M8 can be fetched for under $150 these days. The M7 for under $80. They were about $600+ when they first came out. After a year, less than $300. After two, less than $200. Again, sweet spot for iPhone is around $250-$400. The buyers aren't stupid either. The point that they are buying it used is too save money. Not splurge. For $400, you can easily get a new Chinese flagship.
Honestly, any phone shouldn't be worth over $400 when first bought. People complained about a Panasonic 3DO for $700 or PS3 for $600. My favorite current phone (Moto E2) is only $30 and does like 90% on what I need and does somethings better than my more expensive phones. Now people are buying $700 flagships, left and right? Doesn't make sense. Only the Chinese like ZTE, OnePlus, and Xiaomi value flagship specs accordingly.
About $400 should be tops for any phone including iPhones and Galaxy Notes. It should trickle down eventually like what happened to laptop computers that used to fetch over a grand and 1080p TVs. Remember, we used to pay $400+ for an mp3 player like an iPod over a decade ago. SE will retain its value better by maybe $100 but the 7 will fetch you more money.
If you hate glass backs or don't care for a new design, then go for broke with the 7. Apple will likely use the 8 glass design for the next three years. All that whining about a jet black 7 scratching easily won't look so bad when they return to glass next year which isn't just prone to scratches, but spiderweb cracks. I can imagine iPhone 8 looking like the S7 edge without the curve, edge to edge, and no top and bottom bezel. If you want to wait for that 8 design, then get SE to save cash or wait for the 7 price drop in a year if the 8 design doesn't fancy you.
Sell off the 5s to help with the funds. The 5s should be running like crap by iOS11 next year now that the 5 runs like molasses with iOS10. Planned obsolescence. Apple loves money more than their worshippers...
You're welcome.