But characters within stories and novels should also read widely and well. Why? Because having hobbies and pastimes can be one aspect of bringing your characters to life and reading should be amongst them. Others can include sport, arts of all kinds and so on.
My Fairy Queen, Roxannadrell, reads light romances and scoffs chocolate, one of the Fairy Kingdom's favourite imports from Earth, when she's on her own in her study and wants a break from the far more boring state papers she has to read and sign. Eileen reads history, she feels there is much to be learned from the past, and some crime novels. (She likes to look for motivations in the characters and then compares these with criminals she apprehended, and usually turned into frogs, back in her days in the Fairy Kingdom).
Jenny also enjoys reading but has gone right off fairy tales since discovering she is the daughter of a fairy godmother. Brankaresh reads the kind of self help manuals which will help him gain power. Hanastrew likes crime novels and thrillers. Melanbury and L'Evallier like reading about art. So a character's choice in books and stories can add depth or confirm aspects of their characters and can act like a kind of shorthand. Reading about art, for example, does convey the thought that those doing so are likely to be from a privileged, rich background. (This shouldn't necessarily be the case but it is most likely).