Graphical presentation of age-metallicity degeneration in isochrone fitting of the studied systems on the [Fe/H]_init vs. log(τ) planes. Orange symbols represent the accepted isochrones in fits constrained only by the RV+LC (for SB2s) or LC-based (for SB1s) parameters. Blue points are accepted isochrones after including spectroscopy in the set of constraints. The white stars mark the isochrones that contain the best-fitting models. Significant reduction in allowed ages and initial metallicities is clearly seen in almost all cases, even when spectroscopic parameters were not well constrained. The SB2 systems are shown on the top three rows (without RZ Eri), while the two SB1 systems are shown in the lowest one.