Borderline features in adolescents are associated with emotional instability, self-harm, suicidal behaviour, relational difficulties, and impaired everyday functioning. Because the clinical picture is variable and strongly context-dependent, one-time assessment often fails to detect deterioration, partial improvement, or treatment response. The aim of this paper is to discuss the clinical value of routine outcome monitoring in adolescents with borderline features and to identify the domains most relevant to psychiatric practice. The most important of these include emotion dysregulation, self-harm and suicidal risk, socio-emotional functioning, school and daily functioning, and treatment engagement. Routine outcome monitoring may support safer, more flexible, and more individualized care planning.