I like the idea of the documentary as a portrait. There's not a chronological beginning, middle, and end structure. You build something in the editing room that's shaped by getting to know the person and digging deeper, unpeeling the layers of them as you get to know them.
I was in and out of comas until I was nine and I would lose entire days and weeks. The novelty of being able to really do stuff hasn't worn off - I still feel like I'm making up for lost time.