When should I start seriously studying openings?

Hi, so I just broke 1500 otb in my last USCF tournament, and I was just wondering what are members' thoughts on when I should start seriously studying opening theory?

Right now I play the French against 1. e4, and like to play the Scotch, but there are continuations and lines that I don't know well. I know the common advice is for beginners/intermediate players to focus on themes of quick development and central control in the opening, but at which point would expanding my opening repetoire translate into a gain in ratings?

Should a player at my level (1500 otb) even worry about studying opening lines, or would I improve faster by studying other areas, like tactics, midgame understanding, etc.?

Thanks in advance :)

When you get to the expert level (2200 uscf?) that when you can start study the opening seriously.

I agree completely what pellik said. You don't need to memorize hundreds of variations. Just pick few important variations of your current opening repertoire and play few games using each. Later, analyse them here on chess.com and improve from your mistakes. This much preparation is enough untill you break 2200 barrier.