Summary of the maximal depth reachable at the classical confusion limit as a function of wavelength and comparison with the expected PRIMAger instrumental depth. The left panel shows the survey depth for the required payload sensitivity, and the right panel corresponds to the conservative estimated sensitivities predicted by the instrumental teams. The open and filled upward triangles correspond to the 5σ instrumental sensitivity in the wide and deep surveys, respectively. The solid, dotted, and dashed lines are the classical confusion limit, 50%, and 80% completeness flux densities, respectively. The blue symbols correspond to quantities derived from intensity maps (discussed in Sect. 6.1) and the red from polarization maps (see Sect. 6.2). Note that the flux density of a given galaxy is a factor of ∼100 lower in polarization than in intensity, since the mean polarization fraction is 1%.