Probability distributions of the difference between gyrochronology ages and evolutionary model-derived ages for the brown dwarf binaries Gl 417BC (violet) and HD 130948BC (blue). Multiplying these two distributions gives the joint constraint (black). For both systems, all three models predict ages that are too young based on the measured total masses and component luminosities. This indicates that model-predicted luminosities are too low for these binaries, which have similar component masses (≈45–60 M_Jup) and indistinguishable ages of around 800 Myr.