Time spent on different regions of the HR diagram for stars with mass M = 20,  30,  40,  60, and 80 M_⊙ at Z = 0.002 and Ω/Ω_c = 0.6. In the upper panel, the color code represents the quantity τ_HRD, in yr dex⁻¹, which is the time spent to move by 1 dex in the HR diagram. Green circles are WRs in the SMC ,and blue squares are O-type stars in the SMC with v sin i > 200 km/s from (Mokiem et al. 2006; Bouret et al. 2013, 2021; Ramachandran et al. 2019; Dufton et al. 2019; Rickard et al. 2024; Backs et al. 2024). In the lower panel, the color code represents different burning stages: core H-burning (blue), He-burning (orange), carbon burning (red), and oxygen burning (green), while the line styles represent different wind regimes: dotted for optically thin winds, solid for optically thick winds, dashed for WR-type winds. Cross markers are spaced by ∼ 5 × 10⁴ yr each. After the main sequence, stars spend most of their time at the turn-off point, where they start to peel off their H-rich envelope and move blueward, and in the hot WR phase, at 4.9 < log(T_eff/K) < 5.2.