I was rewatching Mirai Nikki and saw Episode 15, and it got me thinking. Is it a requirement for your phone to be always on?
We already know that 'Future Diaries' are, in other words, your future. So if the phone breaks you have no future which means in short that you die.
So my question is: what happens for example if you decide to put your phone into shutdown mode? Do you still die?
Also how exactly are their phones powered? PS: Magic does not count.
I will accept Manga answers as I do not think it was explained in the anime. Also I have not read the manga so I am not sure. I will also accept answers with a bit of opinion as long as it is a good answer with some sort of canon. :)