For a custom to have legal validity and to be considered as a part of the customary law, certain requirements must be fulfilled.First of all, a custom must exist for a long period of time; it should have the characteristic of antiquity. Secondly, the custom should have the characteristic of continuity; it must be continuously observed. Thirdly, the members of the society should believe consciously or unconsciously in the rightness of the custom. Fourthly, a custom may not be applied if it is in conflict with the written laws. Lastly, there is a need for a state sanction. Until a court applies a custom and gives it the sanction of state authority, it shall not be considered as a part of the customary law.