The opening is nowadays probably one of the most studied of the three phases of the game. We have always said that there should be a balance between the time given to each of them in your training schedule and that it’s more important to get a good understanding of the game by studying a lot of classic games, as well as middlegame and endgame concepts and key positions. However, you shouldn’t misunderstand this.
In order to get to show your knowledge, you must first achieve a good position from the opening. What we mean is that, if you are a club player, it probably makes no sense to memorize a large number of complicated variations only to quickly collapse once the theory is over.