Low-temperature dephasing in disordered conductors: experimental aspects

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.