Studying the age-dimension of the probability distribution of pensions while assuming steadily rising real wages and time-invariant benefit-rules, two factors play important roles: (i) the weight of the wages in indexation of benefits in progress; (ii) the longevity gap. Factor (i) acts against relative depreciation of older benefits, while factor (ii) raises the share of higher benefits among older cohorts. Using an example and a model we show how the shape of the average benefit--age-curve depends on the relation between these two factors.