You can never plan the future by the past.

What happened before tells you how things worked under conditions that no longer hold. It is useful as evidence and dangerous as a template, because the temptation is to run the last plan again when the situation has quietly changed underneath it. Most confident forecasts are descriptions of the recent past with the dates moved forward. The past explains; it does not predict.

Take a plan you are making and ask which assumptions come from how things used to be. Test one of them against current conditions rather than memory. Then leave room in the plan for whatever you cannot see yet.