We study the desorption of self-assembled grown InAs quantum dots with in situ electron diffraction. The time up to quantum dot formation and the post-growth lifetime of the dots are recorded as a function of the temperature and of the arsenic flux. We find a reduction of the post-growth lifetime with temperature and a stabilization of the dots by a sufficient arsenic flux. The shorter lifetime at higher temperatures corresponds to a longer time needed for quantum dot formation. The indium sticking coefficient during growth as well as the post-growth desorption lifetime are calculated with a layer-based desorption model. The calculation results well describe our experimental data.