“Walimah is only in five occasions: in the 'Urs, Khurs, 'Idhar, Wikar and the Rikaz - 'Urs is when a person gets married; and Khurs is when a child is born; and 'Idhar is on the circumcision of a baby boy; and Wikar is when a person purchases a house; and Rikaz is when a person returns from Hajj.”

Source: Wikiquote