Abstract Many properties of metallic thin films have been shown to oscillate with film thickness due to quantum size effects, i.e. the confinement of electrons inside epitaxial metal overlayers which causes quantization of the electronic states. This is a very general phenomenon and it affects both bulk properties of the films, such as resistivity or superconducting transition temperatures, and surface properties, such as chemical reactivity, diffusivity, thermal stability, i.e surface roughening transitions. In this paper we describe some of these thickness-dependent properties which affect the stability of nanostructures and allow us to tailor their properties. We shall concentrate in the paradigmatic example of thin films of Pb grown on metallic and semiconducting substrates and how one can achieve the growth of highly perfect, atomically flat, epitaxial films on different substrates, due to the kinetic constrains imposed by the presence of QSE, a topic increasingly important in the production of nanoscale quantum devices.