What is an acquired right?

A term of employment is considered an acquired right if it has remained unchanged for a certain period and the employee could reasonably assume that this term would continue to be part of his or her package of employment terms. The right is thus “acquired” over time. A key factor in this determination is whether the employee could reasonably rely on the existence of a genuine right that he or she would subsequently possess; in this regard, (but not limited to) how long this “practice” has been in place, what the parties have promised or agreed upon in this regard, the advantages and disadvantages of this right for the parties, and how many other employees have the same right. These factors may be (partly) determined by what the parties could reasonably expect from one another based on the principles of good employer-employee relations (Article 7:611 of the Dutch Civil Code).