Perceptual deterrence has been an enduring focus of interest in criminology. Although recent research has generated important new insights about how risks, costs, and rewards of offending are perceived and internalized, there remain two specific limitations to advancing theories of deterrence: (a) the lack of panel data to show whether issues of changes in perceptions over age and time are linked to changes in offending and (b) the lack of research on perceptual deterrence of active offenders, arguably the most policy-relevant group for these studies. Using longitudinal data on offending and perceptions of risks and punishment costs for a large sample of serious youthful offenders, the authors identify significant heterogeneity in sanction threat perceptions generally and across different types of offenders. These differences in perception reflect variation among offenders in the amount of prior information on offending on which individuals may be basing their perceptions. There likely exists a potential "ceiling" and "floor" of sanction threat perceptions, indicating that there are deterrence boundaries beyond which some types of offenders may be more amenable to sanction threats whereas others may be undeterred by sanction threats. Directions for future theoretical and empirical research are discussed.