Mass loss is an important ingredient in the evolution of stars, in particular during late stages of stellar evolution, when mass loss often is the dominant factor. The far-IR window enables to probe the outflows of evolved stars at different depths, providing direct access to the driving mechanisms. The spatial and spectral resolution of Herschel offer important clues to study the geometry and the composition of the circumstellar gas and dust, and to describe and understand the spatial and temporal variability of the mass loss from initially spherical stars.