  What is the lowest temperature to which one can trace the growth of the
dephasing time in low-dimensional conductors? I consider the fundamental
limitation, the crossover from weak to strong localization, as well as several
experimental reasons for frequently observed saturation of the dephasing time
(hot-electron effects, dephasing by external noise). Recent progress in our
understanding of the electron-phonon interaction in disordered conductors is
also briefly discussed.
