IR-luminous galaxies are the ultimate stellar nurseries and amongst the most massive galaxies at all redshifts. They are thus key ingredients in our understanding of galaxy evolution. I will present results from our work which uses the deepest Herschel surveys of COSMOS and the Chandra deep fields. We have performed a census of the infrared properties of IR-luminous galaxies up to redshift 2 and examined how these evolve with cosmic time. Through careful analysis of survey selection effects, our study has taken place within a framework almost completely free from biases. I will give an overview of our main findings, focusing on measurements of the average dust temperature and IR SED shape and the implications of our results in the broader context of galaxy evolution. In addition, I will review the types of SED models which can best describe the IR-luminous galaxy population. I will conclude by highlighting outstanding questions that still need to be addressed.