This work will provide an updated overview of our understanding of several key reliability issues for SiC power MOSFETs related to threshold-voltage stability. Threshold-voltage instability likely occurs due to the charging and discharging of near-interfacial oxide traps in response to a change in gate bias. If enough traps change charge state, it can lead to significant shifts in the threshold voltage, which may in turn lead to increases in leakage current in the off state, or increases in on-state resistance in the on state. An important question is, what is the best—or most appropriate—test method to use to determine the reliability of these devices. It has recently been observed that one commercial device manufacturer has quite large instabilities, even in previously unstressed devices, and that such large instabilities can result in significant increases in on-resistance during normal switching conditions, thereby degrading circuit performance. Other issues addressed will be the effects of AC Stressing, measuring both static and dynamic threshold voltage, and comparing effects in trench and planar geometry devices.