ABSTRACT Norman Daniels suggests that the just distribution of resources between different age-groups is determined by the choice a prudential agent would make in budgeting resources over the different temporal stages of a single life. He calls this view the “prudential lifespan account” of justice between age-groups. Daniels thinks that the view recommends a rough kind of equality in resources between age-groups. I argue that in the case of a single life prudence would choose an unequal distribution of resources. Consequently, using prudence to model distribution between age-groups might severely restrict the share of resources assigned to the elderly. If we think that extreme inequality between age-groups would be unjust, we should continue to think of justice between age-groups as a problem concerned with the relationship between different lives. But we should apply the requirement of equality to the temporal parts of lives, not just to complete lives.