73 "Extreme unction," which may also and more fittingly be called "anointing of the sick," is not a sacrament for those only who are at the point of death. Hence, as soon as any one of the faithful begins to be in danger of death from sickness or old age, the fitting time for him to receive this sacrament has certainly already arrived.
Source: Sacrosanctum Concilium (Vatican.va)