Maximum value of S₈₇₀, S_870, max, reached across the formation history of massive quiescent galaxies (MQs), as a function of stellar mass at redshifts z = 2, 3, and 4 (from left to right). The data points are coloured according to the redshift at which S_870, max occurred, z(S_870, max). A strong correlation is found between the stellar mass of MQs and their S_870, max, with a dispersion that also correlates with z(S_870, max). At fixed stellar mass, MQs that reached S_870, max at earlier times tended to exhibit brighter S₈₇₀ flux densities.