Evolution of the modification factors of the relaxation rate (top panel) and the scale height (bottom panel) of the stellar disk, assuming steady formation of disk stars that ceased at 150 Myr ago (green vertical line). The factors A_m and A_d account for the modifications from the evolving stellar population and the disk structure, respectively. The overall modification, denoted as the factor A_e, is a mass-weighted combination of the contribution from the young disk stars and the old NSC stars.