PHOTOS are typically the biggest consumers of storage space in iOS devices but not necessarily in that order. However if you are not allergic or otherwise opposed to iCloud Drive, Apple has help for you in the form of optimized images stored on your iOS device. An optimized image has been adjusted in size, color depth, image resolution, etc. for optimum display on the iOS device screen and if taken using iOS 11 & 12 may be in Apple's revolutionary HEIF format (smaller file higher resolution). The original full size image is stored on iCloud and when you edit, print, mail, that image from the iOS device the full size image on iCloud is used, not the optimized image. That is all totally transparent the the user.

To activate this feature:
  • Go to Settings > Photos > Photos
  • Turn on i Cloud Photos
  • ✔ Optimize iPhone Storage
  • Turn on View Full HDR (Recommended not required)
  • this may take a few days to setlle but you may see 60% reduction on storage used on your iOS device with little or no noticeable reduction in functionality.


MESSAGES

Sometime this month or next Apple will release iOS 12 and in Messages in iOS 12 is a feature that allows you to delete an entire "conversation" of messages in one operation.

MUSIC

Music is neck and neck with Photos as a storage eater. The "trick" here is to turn on iCloud Music Library in Settings > Music. Then you can stream your tunes, playlists, etc as long as you have WiFi and if not you can download the ones you are interested in currently.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein