Leaving the parental home is not "an exact science" (Jones, 1994:36). The phenomenon of human mobility (in which the process of leaving the parental home can be included) is “extremely complex, far more than any other demographic event” (Breschi e Manfredini, 2004: 221). The process of leaving the parental home is still a demographic event that causes and suffers effects in the other spheres of life and in other lives.
For instance, the timing of leaving the parent’s home is mainly determined by the school trajectory (especially its longevity), by the professional trajectory (in particular, at entry into the labor market or remuneration aspect of the professional activity) and by the romantic or marital trajectory that still tends to mark very much in Portugal, the departure from the parental home (longitudinal effect, with leaving home as the dependent variable).
From a different perspective, the individual departure from the parent home also has a major impact on the dynamics established in the household of origin, either through the “empty nest” phenomenon, the change in the relationship of the remaining siblings with their parents, or the housing readjustment or the intergenerational supports (extra-linked effect, with leaving home as an independent variable).