Among the status-conscious Iban, these names provide links with their illustrious forebears. Membership in a bilek family, and hence the longhouse, may be by birth, marriage, or adoption. A family may also join a longhouse because of ties of friendship. Postmarital residence is called utrolocal, which is an equivalent concept to ambilocal residence. Uxorilocality and virilocality are equally common.
Preferred marriages are within the kindred, especially with first to fifth degree cousins.
Marriage within the longhouse is as common as marriage outside. The Iban are strongly monogamous, but in the early years of marriage, divorce is simple and not uncommon. Inter-ethnic marriages, though dangerous in some ways, often help to establish and maintain advantageous commercial relations. Recently, educated Iban have tended to marry later. They are looked on as valued marriage prospects, regardless of their backgrounds, because of their high earning potentials.