Greedy iPhone

Mosty of the time the devices around us just work. Which makes the occasions when they go wrong all the more scary. Yesterday my iphone started moaning about being short of memory. Which was surprising, bearing in mind I don’t do things like record videos or put lots of huge games on the device. I thought I’d sorted out the problem by deleting a few movies I had downloaded but today it ran out again. Something in my phone is eating all the memory. Searches online list a bunch of things you can do to try and fix this which end with the action “wipe the phone and restore everything”. Ugh.