According to iTunes, on my iPhone 6 I have 6 Gb Photos, 2 Gb Apps, 1,4 Gb Documents & Data and 1,6 Gb of Other. I have no idea what Other is and what makes 1,4 Gb of Documents.
I want to free as much space as possible without deleting photos and apps. If I backup my iPhone using iTunes, make a factory reset and then restore the backup, will Documents / Other be completely restored too or will I gain free space?