Sometimes it's the wrong stuff and you have to track back and redo large stretches of the plot because the last way fizzles. (Outlines. Marvelous things. Slicing out maybe a page to entirely redo the plot. . . )
But sometimes it's just one possibility. Pondered the possibility of throwing in another character earlier into one story in the outline stage. It would have altered the story entirely, which is good, since character is plot, and introducing a character ought to change the plot. . . but I had already written a chunk. . . and finally decided that economy was the key. Superfluous characters have no place in a story and so should not be added.
Maybe I'll write that character into another story.