There should be no departure from a common observance.

Explanation

A long-established legal practice or custom carries the force of law until expressly abrogated — cite this to challenge novel statutory interpretations or administrative rules that depart from settled usage without clear constitutional warrant.

Where this applies

• A court tries to change a well-established practice without strong justification.
• Someone departs from a settled observance with no compelling reason.

See also

• 1.2.2 The general custom of the whole country is the common law of the country.
• 1.3.1 Custom is the best interpreter of the law.