Hα equivalent width profiles in star-forming galaxies at z ∼ 0.5 (Matharu et al. 2022), z ∼ 1 (Nelson et al. 2016a), and z ∼ 5.3 (this work). The small thick vertical lines show the continuum R_eff measurements for each stack. Left: At fixed stellar mass, star-forming galaxies that form earlier grow inside-out via star formation more rapidly with galactocentric radius. Right: If a galaxy forms stars at a constant rate between 5.27 < z < 1 and 1 < z < 0.5, starting with a stellar mass of Log(M_*/M_⊙) = 8.62 at z = 5.27 (see Section 4 for details), it will rapidly grow its inner region via star formation with radius, after which there will be steady growth at z = 1 and then rapid growth of the outer region with radius at z = 0.5.