Upper row: 1σ envelope of the age relative error in dependence on the mass of the primary star (left panel), and on its relative age (right panel). The solid black line corresponds to accounting for correlations in covariance matrix (see text) and assumes that the stars are coeval; the red solid line assumes the same covariance matrix without assumption of coeval stars in the recovery (see Sect. 2); the dashed line assumes coeval stars and a diagonal covariance matrix. Lower row: same as the upper row, but for the secondary star.