Active Galactic Nuclei (AGN) are not longer considered part of a small and exotic source population but are now widely accepted to play a significant role in the evolution of galaxies through cosmic time. However, even fifteen years after the realization of the close link between the mass of the black hole and the properties of the hosting galaxy many details of the interconnection remain unresolved.  Two complementary approaches are followed to deepen our understanding; detailed studies of individual nearby AGN provide insight into the physics that trigger AGN activity and link it to the spatially resolved host properties, while the large samples of AGN collected from surveys access the population properties and their impact on the evolution of their hosts with redshift and environment. This second approach is hampered by technical challenges that can severely bias the results. In my talk I will focus on how these challenges (such as, e.g., multiwavelength counterparts identification and redshift determination) where solved in surveys of few square degrees (e.g., COSMOS, XMM-XXL, Stripe82X) and show how what we have learned so-far can prepare us to the new challenges that the next generation of wide-angle and all-sky sky surveys of galaxies and AGN (e.g., SRG/eROSITA, EUCLID, LSST, ASKAP/EMU) will pose.