OH. IT'S JUST ONCE A WEEK. THANK YOU, SORRY FOR THE CONFUSION.
Hey there! Thanks for the feedback! You can actually also save by exiting the game to Main Menu, but this isn't really properly stated in the game. We wanted the game to save when you directly exit the game too, but there were some problems that we couldn't fix in time for launch. We'll try to do something about the issue in a future patch if we can figure it out.