Dust-to-stellar mass ratio as a function of stellar age. Top: GAMA galaxies (light grey dots) and exponential fits for redshift bins up to 0.9. Bottom: DD20 galaxies (grey cross markers) and exponential fits for redshift bins from z = 0.9 to z∼5. Vertical dashed lines represent the age of the Universe at the corresponding redshift (colours correspond to the redshift bins). Plots for the individual redshift bins and fits are included in Appendix A.1.