AnneandJerry Said:
"Data Storage: On Saturday evening, my wife and I received notices that our storage was nearing capacity on our two phones at almost 1 GB each.[...]"
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Troubleshooting iPhone Storage:
Internal storage cannot be upgraded. It is what it is. So, it will not have changed, even if you upgraded your iCloud plan. Learn More here: What's the Difference Between Device Storage and iCloud Storage? Apple Support
So, what to do:
Clear Space:
Try clearing internal storage though use of the following:
What Space to Clear:
A. Clear Temporary Internet Files:
Clear your Temporary Internet Files(Cookies & Cache) of Safari:
Also...
B. Clean TV and Music Libraries:
Remove all unneeded files from your TV and Music Libraries. Full-Movies take up 2-4GB typically, and a bunch of those would take up a load of storage, ideally. So, if you have any movies that are not needed, then delete them.
Also..
C. Clear "Other":
Clear the storages named "Other". It basically contains unnecessary files such as caches that are used for system ease of use - all of which gather over time: How to Clear "Other" in your iPhone's Storage - Use Backup - User Tips. Caches would be being used for remembrance of application use. So, clearing other may be the way to go about this, as it would be performs through use of a computer.