Security fatigue—exhaustion caused by security demands—was found to affect security compliance. While the current body of research has increasingly used cross-sectional methods, fatigue’s temporal effects on protection behaviors remains underexplored. This work adopts an idiographic approach to investigate how fatigue evolves over time and affects individuals’ protective security behaviors. Drawing on Affective Events Theory (AET) and Social Support Theory (SST), we examine how security communication moderates this relationship. Using hierarchical linear modeling (HLM), we aim to investigate within-person variations across multiple time points, offering both theoretical and practical insights.