An unexplained number becomes a fact surprisingly quickly.
Put the important assumption in the scenario or item name: “New role, low estimate”, “Rent after July increase” or “Power, winter likely”.
Good assumptions are visible
- What figure did you use?
- Where did it come from?
- What would make it change?
You do not need a research report. A few honest words help future you understand why the scenario looked the way it did and whether it still deserves trust.