Recently I'd noticed my iPhone was getting full without me adding anything much to it. In iTunes I noticed that it was half full 'Other' stuff - WTF?! I realise with a few hundred apps I was pushing things a bit but not that far. I looked around and found this article on cleaning up the 'Other' stuff on an iPhone - I tried its suggestions to no end. But it led me to exploring my phone further...
I noticed that the 'Voice memos' section was loaded up with duplicated audio files some of which were quite large. There's clearly a bug somewhere leading to this (I'd seen this kind of duplication bug in iTunes for music tracks before but it seems to be fixed now - but not so for Voice memos).
So the way to get rid of them and clear out the 'Other' category is to use the iExplorer (or similar - Ubuntu etc can mount an iPhone so you can see these things) software and navigate to Media/Recordings and delete all the duplicates recordings. The problem is that it seems the bug persists... so to really clear it up you need to make sure you've got copies of the memos you want (they should be in iTunes but make sure before the next step - if they're not then use iExplorer to export them out or failing that obtain them from a backup with a backup explorer - iExplorer crashed when I tried to export them). Now delete ALL the memos from Media/Recordings using iExplorer. Then go to your phone and tap on the Voice Memo's app and then tap on the bottom right button to ensure that they're all gone (if necessary you may need to quit the app and restart it). This should sort out the Voice Memos database for future use, and also seems to put iTunes straight.
Now sync with iTunes and you should see most of that 'Other' space reclaimed (some is legitimately used by certain apps for internal storage) and available once again...
