One bad experience can install a defense that runs for decades. The betrayal, the humiliation, the moment of danger occurred once, and the response has been operating continuously ever since, at considerable cost, protecting against something that may never recur. The defense does not check whether the threat is still present; it just runs.

If you have a rule you follow rigidly, ask when it was made and what it was protecting against. Then ask what the actual frequency of that event has been since. Some defenses will earn their keep. Others have been charging you for years against a single incident.