Time-domain observations now offer a promising new way to study accretion and jet physics in X-ray binaries. Through detecting and characterizing rapid flux variability in these systems across a wide range of frequency/energy bands (probing emission from different regions of the accretion flow and jet), we can measure properties that are difficult, if not impossible, to measure by traditional spectral and imaging methods (e.g., size scales, geometry, jet speeds, the sequence of events leading to jet launching). While variability studies in the X-ray bands are a staple in the X-ray binary community, there are many challenges that accompany such studies at longer wavelengths. However, with recent advances to observing techniques/instrumentation, the availability of new computational tools, and today’s improved coordination capabilities, we are no longer limited by these challenges. In this talk, I will discuss exciting new results from fast timing observations of MAXI J1820+070, where we simultaneously sample ten different wavebands (from radio through X-ray) over a range of timescales. With this work, I will highlight how we can directly connect variability properties to internal jet physics, deriving fundamental jet properties from time-series signals alone. Additionally, I will discuss future prospects for obtaining more of these invaluable fast timing data sets, and the key role that next-generation instruments will play in driving new discoveries through this science.