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I believe it's some kind of left side screen press/swipe thing.

Press down firmly on the FAR left edge of the screen, then you'll see a thin bit of the app list show. If you then swipe quickly across you switch back to the last app you were in, if you move more slowly to the right you get your list of running apps like a double click would do.
 
Did you really spend a good 10 mins in each app/browser tab? I could quickly flick between them all on my 6+ but any longer and it would reload. Perhaps I didn't set a stringent enough test...

This would definitely cause my old 6+ to reload. Open up the Ebay app and dial in a seach. Look at a few items, then go and see the price of that item on the Amazon app. Then go and find a retailer's website on safari to check prices. Then open another browser tab and find a review of the item you've been looking at. Now go back to Ebay and see if it reloads, then check Amazon again, and finally Safari.


I didn't do your second round of tests, but I haven't touched the phone since my last post about this, and it looks like nothing's reloaded.
 
I just went back and accessed those same apps through the task switcher and they were still where I left them. I've used the phone all day just like I did my old 6 Plus, and I havent seen reloading on any apps other than the two games I played, Boom Beach and Star Wars Commander. I'm sure it wouldn't be hard to script a situation that causes the phone to eject apps from memory, but I will only be impressed if it performs well running the tasks that I find important on a daily basis. So far, so good.

I agree and that's why I suggested the above test because I'm always using my phone in that manner. The 6+ used to reload my stock Notes app too and that really bugged me because I keep a work diary on it and add to the note three or four times a day. By September it's a loooong note and I was having to scroll to the bottom every time I went to the app. Not the best solution for a diary I know but it worked out fine on the iPhone 5 and I kinda stuck with it.
 
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