In Nigeria, Yoruba people typically wear Aso-Oke (sometimes spelled Aso-Ofi) on special occasions. Typically, chieftaincy, festivals, and other special occasions call for this particular attire.
The days when wearing an Aso-Oke (Aso-Ofi) was a way to emphasize a person's wealth or royal status are long gone. Then Aso-Oke would just be Iro and Buba (wrapper and blouse).