Are leaders more likely to face militarized challenges earlier in their tenures? Existing studies posit contradictory hypotheses, as new leaders can both invite challengers to take advantage of their lack of preparedness, and deter challengers by their strong incentives to build a reputation for resolve that will stave off future problems. This paper reconciles these competing tendencies by developing a conditional explanation that centers on the direction of the new leader’s anticipated foreign policy preference shift in relation to the previous administration. From the challenger’s perspective, if the office in the target state is passed from an incumbent dovish leader to a hawkish successor, then a more pessimistic strategic environment arises where the new hawk can be less satisfied with the status quo and seeks to revise it. Under this scenario, the new hawkish leader’s inexperience and strong reputation concerns tend to amplify the challenger’s fear of suffering an immediate loss. The challenger, therefore, has incentives to initiate an early crisis to educate the more hawkish but also relatively less informed newcomer on the challenger’s position, resolve, and capability. Otherwise, the opportunity costs of an early challenge—disrupting a potentially beneficial and warmer relationship between two countries—tend to constrain the challenger from provoking an inexperienced new dove whose reputation concerns are high. Statistical analyses of leadership turnovers in all major powers during the post-WWII period (1945-2010) largely support this conditional hypothesis.