\label{fig:medsed} Median SED of class II sources in clusters of various evolutionary stages: NGC1333 (magenta, 1 Myr), Trapezium COUP sources (black, 1 Myr), Taurus (green, 1–3 Myr), NGC1980 members (red), \(\lambda\) Ori (blue 5–7 Myr) and \(\eta-\)Cha (orange, 5–10 Myr).