Knowing which battles to fight is more important than being a good fighter.
This isn't to say that we shouldn't learn the skills and gather the tools of a good fighter, because when the chips are down and you're backed into a corner, it's do or die.
But if you fight every battle that comes your way, you're going to wear yourself out, likely before you get to the crucial one.
So pick your battles.
And while you're waiting, sharpen your sword.