Evolution of the convective turnover time at different depths within the convective envelope as a function of effective temperature on the PMS (top), from the ZAMS up to the RGB tip (middle), and from the beginning of central helium-burning up to the end of the early-AGB (bottom). The vertical lines indicate the beginning and the end (solid and dashed, respectively) of the PMS, of the central H- and He-burning phases, and of the first dredge-up (in blue). Left and right figures correspond to the 2 M_⊙ standard models computed at Z_⊙ and Z = 0.0001 respectively. The magenta lines that are associated to τ_c(H_p) are sometimes interrupted; this corresponds to evolution phases when the radius at a pressure scale height H_p above the base of the convective envelope becomes larger than the radius of the star.