Dust disk mass with time. Panel a: for the categories of these works. Their average is shown to the right. The error bars in the bottom area are representative of different ages while those on the disk mass are comparable to the symbol size. Panel b: labeled version of panel a. Inclined disks are not included. Disks where an outer stellar companion is present are indicated by the twin dots. The best-fit to our data is shown as a dashed line. The median of Taurus, Lupus, Chamaeleon, and upper Scorpius is shown as crosses. Panel c: same as panel b, with the age being normalized to the ZAMS (see text). Panel d: only sources belonging to the main SFRs. Here small disks are indicated by the black dot and inclineddisks by the horizontal bar.