The last 2 decades have witnessed increased research on the role of life events in personality trait development, but few findings appear to be robust. We propose that a key to resolving this issue is incorporating individuals' subjective experiences into the study of event-related development. To test this, we developed and administered a survey about event-related personality change to a representative Dutch sample (N = 5,513, Ages 16-95) and linked their responses to 12-year trajectories of measured Big Five development. Most participants (63%) believed that a life event impacted their personality in the past 10 years, on average 5 years presurvey. These participants, even those who experienced the same event, had markedly heterogenous perceptions of how their traits changed and why each event affected their personality. In preregistered analyses, we examined participants' individual personality trajectories before and after the event that they identified as most impactful. Across events, retrospective perceptions of event-related personality change were significantly correlated with short-term and long-term postevent personality trajectories across Big Five traits (mean rs = .22, .28) and preevent trajectories in all traits except agreeableness (mean r = .16). We also found correspondence between perceived and measured development in analyses of the two most commonly reported personality-changing events: health problems and death of a loved one/family member. Finally, we explored associations between personality development and perceived change-inducing event characteristics. Using these findings, we argue that future research into event-related personality development should de-emphasize mean-level change to focus on individuals' varied experiences of whether, when, how, and why life events have affected their personality.