When does app re-initialize? Seems random

When using my app, I currently have a login system that isn’t using local storage yet (it will be soon - to store an API key) but right now, it’s just in the $scope of main controller.

I can’t seem to figure out when/how/what is the criteria for when the app will “re-init” and go back to the login screen.

It seems to be just “after a while” the next time I load the app, it’s as if it’s a first time load, as opposed to just opening on the last page I was on.

Does anyone know the exact criteria for when it will “re-init” and go back to the default route, and/or when the splash screen will appear - I assume this is on first app load only, but would be nice to get some clarity!