This article seeks to shed light on the problem of recurrent international conflicts. It does so by investigating the relative frequency of a particular class of such conflicts, those in which the challenger in a given conflict is the challenger in the next conflict involving the same two countries. I demonstrate that these “repetitive military challenges” constitute a significant majority of several types of recurrent conflicts. I also develop a Cox proportional hazards model of the risk that, after a given conflict, the defender is re-challenged by the original challenger, a conflict that is usually but not always a repetitive challenge. This analysis finds that a range of systemic, dyadic, and national conditions contribute to the risk of re-challenges. One key finding is that after low-severity conflicts, democratic defenders are at a greater risk than are nondemocratic defenders to be the victims of re-challenges.