Can 1500 players benefit from opening theory?
I've heard over and over as I learn chess that really I shouldn't bother with learning openings. Memorizing lines might be fun, but at some point you are going to have to play chess and that low rating will show itself quickly. lol While I totally agree with that point, I do want to argue against the idea that a 1500 player like myself can't benefit from it, because I certainly do and all the time! In fact, it can have a huge impact on my games in either direction.
There are some openings I just know very, very well. While I don't make it a point to study these openings deeply, I do analyze my games and so every game you learn the "next step" in the opening (or maybe 2 or 3..hehe). Over time this builds some knowledge ya know? You find traps. You find plans! And when I study an opening I am not content to just memorize the book moves. I do my best (with the help of my friend Stockfish) to figure out just what the point of the moves are. That way I know why I'm playing a move.. what I might be preventing or allowing.. and I also know 1.) if my opponent is playing the book move or not and 2.) why that move should be played and then with that knowledge, often you can figure out ways to punish it.
On the flip side, I sometimes I play openings I don't know very well or just feel uncomfortable like I don't have a middle game plan. And perhaps not surprisingly, I sometimes get completely crushed when this happens. I actually got move ordered into a Psuedo-Catalan from the black side not too long ago (what the heck is that?? lol) and got crushed in just 11 moves. A heartbreaker to be sure. Sure, I wish I was good enough to avoid those scenarios completely, but I'm not yet, and I have to ask; would that ever happen had I known the opening?
But sometimes it works the opposite way as in this game where black gets crushed playing an Albin Countergambit in a 5/5 blitz game. I knew the opening, I knew the theory, I knew when black went of book and why he should have played the book move. And then found a way to challenge it.