Discipline Education Series: Past Practice
Finally, think about the relationship. The business or agency has a mission. The past practice doctrine is powerful because a binding past practice becomes a term of the CBA. This makes sense because parties adopt practices to meet the needs of the business or agency. It is always smarter to think of a binding past practice as though it were a provision in the CBA.
In the end, you can always negotiate for something else in the next contract.