Ask HN: Are there mental models that CTOs rely on regardless of company stage?

The idea is that these frameworks help answer questions at the MVP stage and at the scaling stage and beyond. I'll throw out a few to get the ball rolling:

Urgent/Important Matrix

Stakeholder Mapping

Cost/Quality/Speed triangle

Irreducibility (9 women 1 month pregnant example)

Redundancy

Margin of safety

Opportunity Costs

Bottlenecks