As part of our book diet, C.S. Lewis reminds us to not leave out old books. “It is a good rule, after reading a new book, never to allow yourself another new one till you have read an old one in between. If that is too much for you, you should at least read one old one to every three new ones” (C. S. Lewis, “On the Reading of Old Books”).
Lewis is wise to also say that,
“People were no clever then than they are now; they made as many mistakes as we. But not the same mistakes. They will not flatter us in the errors we are already committing; and their own errors, being now open and palpable, will not endanger us. Two heads are better than one, not because either is infallible, but because they are unlikely to go wrong in the same direction” (C. S. Lewis, “On the Reading of Old Books”).