I will discuss a complex-valued generalization of Wigner time delays for systems with uniform absorption and its implications for counting S-matrix poles in mesoscopic systems. On one hand, this approach allows to extract the density of such poles from experiments in microwave chaotic graphs, and on the other hand provides a unified framework for describing such density analytically in a broad class of disordered mesoscopic systems, including the regime of Anderson localization. The talk will be based on recent papers with L Chen and S. M. Anlage [arXiv:2106.15469 and arXiv:2101.08335], as well as on a work in progress with M. Skvortsov and K. Tikhonov.