If you had to choose one: opening theory or endgame technique?

Still being newer, this is something I wonder myself. I think right now I lean toward openings.

Endgame technique will win you more games (and will also save more lost positions) than opening theory will.

Opening study is more fashionable.

Playing against someone at my rating, I'd feel very confident playing against someone with tons of opening theory and poor endgame skills. I'd be nervous if it were the other way around.

Opening, you don’t need to worry about endgame until you get to it. If you can’t play a good opening you won’t need to worry about endgame

There are probably a lot of good analogies. Maybe a race. Which is more important, starting the race strong or a strong finish.

I would say crossing the finish line technique doesn't matter if starting technique is lousy or even average. I'll bet most competitions are won by the person who has an early lead and maintains it. My guess is come from behind wins at the end are far more rare.

Endgame theory of course.

Openings are a PITA.

Being a pita is testimony to why they are more important.

Endgame because as the game progresses your game just gets stronger, as it will also help guide some of your middle game decisions.

Openings are a PITA because you have to just memorize a lot.

Its no fun.

Endgames are fun.