I work at a small finance firm where the projects were ran by one or two people for probably a decade. They didn't rely on databases, or any programming, up until 6 years ago or so and spreadsheets were how they got work done. So when I have to figure out how to do something, I have to click through probably a dozen spreadsheets and track Excel formulas/ad hoc calculations. There's no documentation, presumably because they didn't anticipate anyone else taking over the project. Or maybe it was due to time constraint.

Anyway, I'm not documenting anything either. There's too much work.