Ask users for permission when, and only when, we absolutely need it, and we think the user can clearly relate how this access will benefit them.
only show the system permissions dialog once a user has told us that they intend to say “Allow”.
the worst possible thing is for a user to deny permission at the system level, because reversing that decision in iOS is very complicated. But we ask them before the system does and they say no, we still have the opportunity to ask them again in the future when they are more likely to say yes.
Context is critical. Clearly every app is different, but really thinking about when the user would naturally need access to different parts of their phone, and making sure they expect to be asked, can make drastic improvement to the success of these system dialogs.
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