Memorizing Theory To 30 Moves Is Very Helpful
I have heard in several circles that memorizing theory is bad and that learning how to open properly is better.
I have discovered that when you memorize theory out to 20-30 moves you are actually repeatedly playing through and committing to memory full and complete GM games!
This is such a valuable resource because we learn the secret techniques & thought processes of experts in the game of chess and they cannot help but rub off and manifest themselves in our own games.
Maybe the best way to put it is: "Memorizing theory mindlessly is bad" and with that I certainly agree.