The intra-distributional mobility of German income dynamics is analysed using GSOEP. Transition probabilities are found to be time-varying. The tested models comprise various mixed Markov chains in discrete time and a non-stationary mover-stayer model is proposed. In order to explain the observed mobility profiles, we concentrate on one important income class - the poor - instead of the entire transition matrix. Various poverty duration models accommodating unobserved population heterogeneity and duration dependence are examined.