Why does schema selection heuristics fail?

The most common reason schema selection heuristics fails: Defaulting to the same schema every time regardless of problem structure — Munger's 'man with a hammer' syndrome. You learned jobs-to-be-done, or first-principles thinking, or Bayesian reasoning, and now every problem looks like it needs that tool. The schema isn't wrong. The selection process is absent. You'll know this is happening when you notice you haven't genuinely considered an alternative framework in weeks.

The fix: Pick a real decision you're currently facing. List every schema (mental model, framework, lens) you could apply to it — aim for at least four. For each, write one sentence: what would this schema optimize for? Then answer three selection questions: (1) What is the cost of being wrong? (2) How fast do I need an answer? (3) Which schema have I applied most successfully to similar problems before? Use your answers to pick one schema. Write a brief note explaining why you chose it. You now have an externalized record of a schema-selection decision — the raw material for improving your selection heuristics over time.

The underlying principle is straightforward: You need rules for choosing which schema to apply in a given situation.