The availability of long time series of interferometric data acquired all over the world from several synthetic aperture radar (SAR) satellite missions makes possible to perform a worldwide analysis of ground surface deformations and infrastructure stability by SAR interferometry. When this technology is applied to large areas, several problems have to be faced to handle huge amounts of data. In this work, we present the first example in the world of persistent scatterer (PS) SAR interferometry analysis at national scale (the whole Italian territory), performed with ERS, Envisat and COSMO-SkyMed SAR data acquired from 1992 till 2014. Moreover, we discuss the complementarity of high resolution SAR systems like COSMO-SkyMed, with the new Sentinel-1 SAR satellite, which has lower resolution but larger swath. Based on these characteristics, we explore the possible worldwide extension of our national experience.