Cumulative flare frequency diagram for three selected targets from our sample with different rotation periods. The black solid lines give the power-law fit including all flares above a given energy detection threshold (see text in Sect. 7.4). We also show the power-law fits of Ilin et al. (2019, from their Table 4) for Praesepe (M 44, 630 Myr, red) and the Pleiades (M 45, 125 Myr, blue) in the same temperature range of our selected targets.