And once in the work, there is the question of how much of the detail is relevant, how much of it is convincing clutter, to ensure that the world looks detailed, and how much of it would even impinge on the POV character's awareness.
Sometimes it is relevant. One major character in NaNoWriMo novel is the accountant who keeps track of the goods send to the fortress in payment.
But needing a way to foreshadow the fortress, I put a band of men from it on the same road as our heroine. And then I said they came to get a non-standard payment. . . .
You know, I don't think my heroine would brush them over entirely. She wants to integrate herself at first but would indulge in her curiosity in due time. It need not have any effect on the novel, she might laugh over how something so minor led to her seeing them, but she would know.
I know what they usually send: linen and wheat. But what does this land have that is unusual, and yet valuable enough. . . .
I may make it an escort mission, after all.