It sometimes happens that both spouses die at the same time or within a short time of each other. When spouses die at the same time, under South Australian law there is no presumption (that is, it is not taken as a fact) that the older died first. Where there is no proof of who died first, it may be necessary (for example, where the deceased were joint tenants) to apply to the court for guidance as to the distribution of the estate.
A testator can cover the possibility of both spouses dying together or within a short time of one another, by providing for this in their will. They can say that how they distribute their estate provided their spouse survives them by the required time, and how they distribute their estate differently in the event that their spouse fails to survive them by the required time.