My iPhone 5s currently running on iOS 9.2 has been misbehaving for a couple of months now. No matter, how much free space I give it, it slows eat it away, reducing MB by MB till I have 0 bytes free space left.
Even if I don't use the phone, it stills eat away the free space. My suspect is that an app is writing logs like a maniac. I tried syncing with iTunes thinking it might be the debug logs that gets sent for crashes etc, but it's not that either.
How do I go about getting an idea on what makes up this other data? If I know its an app (I am thinking Whatsapp since its a chat app and the only thing on my phone that keeps on running all the time), I can get rid of it.