Recent observations have shown that the sizes of passive and massive galaxies at z=1-2.5 are on average much smaller than high-Sersic index galaxies of similar masses in the local universe. These results suggest a strong evolution in galaxy sizes, as compact and massive galaxies at low-z have been found to be a small fraction of the field population. I will show new results on compact massive galaxies at low redshift: their incidence and properties in the general field and in galaxy clusters, the evolution of their number density and those effects that lead to overestimating the size evolution of individual galaxies. These findings point to a mild evolution and highlight the need for a revision of the current paradigm.