Begin with the thesis
If a trade depends on support holding, define what holding means. Is a brief move below acceptable? Must the session close above the level? Your stop logic cannot be clearer than the idea it protects.
Separate price logic from account risk
First place the hypothetical stop where the setup is invalid. Then calculate whether the resulting position fits your risk limit. Moving the stop closer only to permit larger size changes the trade and often puts normal market noise inside the exit.
Decide before exposure
Write the invalidation before entry and include known event or gap risk. If you cannot identify a price-based condition, the trade is not yet defined well enough to size.
Use it in your review
Find three recent trades where this principle mattered. Record what you knew before entry, what rule you followed, and one decision you would repeat or change. Focus on evidence visible at the time—not hindsight.