Fault healing (post-seismic recovery of fault-rock strength and permeability) has been invoked as a control on the magnitude, recurrence, and slip speed of earthquakes as well as episodic tremor and slow-slip events. Lack of healing may promote steady creep preventing repetitive failure events. The efficacy of healing processes, however, depends on the relative rates of geochemical reaction and volumetric deformation throughout the seismic cycle. Whereas deformation rates around faults are generally well understood, time scales of physico-chemical processes that dictate healing are poorly constrained by direct observation. Thus, it is rarely demonstrated whether the physico-chemical processes invoked can occur with a magnitude and rapidity consistent with the time- and strain rate-dependence of fault healing. We invite interdisciplinary studies that explore fault-rock healing in the context of the full spectrum of fault-slip behaviors, with an emphasis on the magnitude, rate, and implications of healing processes over single or multiple slip cycles.