I don't know. I user folders heavily and only have 3 pages of apps: Apple Apps on page 1, all third party, non-game apps on page 2, and all games on page 3. It's easy enough for me to remember, but I'd also like to see folders implemented in the Apple Watch layout to see how efficient that could be.
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That's a very unlikely setup for a user to have a folder with 9 pages. iPhone 6 and 6 Plus screens now add another row of icons so it's even less likely. As I said before, I use folders heavily myself on only 3 pages, and my iPhone 6 128GB has 419 apps on it, and I don't have a single folder with 9 pages on it. In fact, I only have one folder that goes up to 4 pages. Every other folder is 1-3 pages each folder, mostly 2 pages.