The observation that individual volcanic centres have their own eruption frequencies has been known for a long time but is as yet poorly understood. The key to a better understanding of the mechanisms controlling the eruption frequency comes from integrating accurate geochronology and geochemical data with numerical models. In many silicic volcanic systems, the eruption frequency is studied for short timescales of <1 Ma. Here, we combine two published numerical models to improve our understanding of the eruption frequency in a long-lived (>3 Ma) felsic magmatic system, the Milos volcanic field. From these two models, we interpret the time intervals between magma pulses into the subvolcanic reservoir (t_i), the rates of magma supply (Q_av) and chamber growth rates (G_mc) as the key parameters controlling the eruption frequency. During the time intervals of 1.5-1.04 Ma and 0.97-0.63 Ma the t_i is longer than 500 years and the volcanic quiescence periods are longer than 350 ka. Furthermore, these periods are characterized by low values for Q_av (≤ 0.001 km³·yr^-1) and for G_mc (<0.0008 km³·yr^-1). In contrast, during the time intervals of 3.3-1.5 Ma and 0.60-0.06 Ma, the t_i is shorter (<0.5 ka) and the values for Q_av (> 0.001 km³·yr^-1) and for G_mc (> 0.001 km³·yr^-1) are higher corresponding to frequent eruptions. The parameters t_i, Q_av, and G_mc appear to determine the eruption frequency of a volcanic system. Changes in one or more of these three parameters of the Milos volcanic field correlate with changes in the tectonic stress field.