Grit: The Power of Passion and Perseverance · chapter 10 · id grit-c10-04-duckworths-hard-thing-rule-has

“Duckworth's 'Hard Thing Rule' has three parts: everyone in the family must do a hard thing, you can quit but only at a natural stopping point, and you get to pick your own hard thing.”

holdsconfidence: high⚠ extracted by pipeline, re-audit pending

Receipts

Advantage Strength - The Hard Thing Rulesource alive
The Hard Thing Rule has three parts: everyone does a hard thing requiring deliberate practice; you can quit but not mid-season; and you choose your own activity.
Inc.com - Hard Thing Rulepaywalled — manual check queued
The Hard Thing Rule allows freedom to choose pursuits but sets the expectation that once started, you see commitments through to a natural stopping point.
Forge Coaching - Extracurricular activities and gritsource alive
Duckworth adds that when her daughters reach high school, a fourth rule kicks in: they must commit to at least one activity for at least two years.

This claim is a stable, citable object. If you can falsify a verdict, tell us — corrections are loud here.