Thesis: This dissertation comprises the research I conducted over the course of my doctoral studies at the Paris School of Economics. The underlying common theme between the chapters is the microeconomic study of poor rural households over the course of time. I focus on changes in these households’ welfare level (intragenerational mobility) and the development of their human capital (intergenerational transmission). The first essay examines whether the timing of a cash transfer program could have an impact on the household’s long-term welfare trajectory. The results suggest that a short time differential in exposure to the program had an impact on the household’s likelihood of remaining stuck in poverty in the long run. The second essay investigates the intergenerational relationship between parental non-cognitive skills and subsequent child outcomes, finding an association that is still detectable after several years. The third essay investigates the risk factors (near birth) associated to children’s developmental trajectories into youth, with a focus on maternal mental health. The results show the development gaps, between poor and stable mental health mothers, widen with time, suggesting the importance of maternal mental health as a risk factor in the early stages of a child’s development. Overall, the ensemble of studies highlights the research insight which may be gained from following households’ or individuals’ trajectories over the longer term with a focus on specific periods identified as critical for development.