All quasars show a common stochastic variability, seen across various observed wavelengths and timescales. The origin of this variability is still uncertain, though variability in the optical is thought to stem from processes in the accretion disk and other structures close to the supermassive black hole (SMBH). Time-series and spectral variability analysis present unique ways to probe a quasar’s geometry and dynamics, including the mass of the SMBH. Much of the analysis used for measuring these structures involves assumed models of radiation and kinematics, which necessitate testing through high-quality, high-cadence data. We present results from modeling quasar optical variability, using high-quality, 20-year-long light curve data, and how it informs our view of the innermost structures around SMBHs. In particular, we find evidence of a characteristic timescale near days long in the optical, and slow, inward-moving propagations in the quasar accretion disk. We mention the future of variability studies, involving high-cadence surveys such as LSST, and multi-epoch spectroscopy campaigns, as well as the finely resolved reverberation mapping data that can be produced.