In an expanding universe, distant events should appear time-dilated by a factor of $(1+z)$. While this effect is well-established for Type Ia supernovae (standard clocks), the variability of quasars has historically shown conflicting results. Some studies (e.g., Hawkins 2010) found no evidence for time dilation in quasar light curves, suggesting either that quasars are not at their redshift distances or that their intrinsic variability timescales evolve exactly to cancel the dilation. Although recent high-redshift studies (Lewis & Brewer 2023) claim to detect the effect, tensions persist regarding the "standard clock" nature of quasar accretion disks and the robustness of the detected dilation against selection effects and intrinsic evolution models.