This chapter introduces person-reported outcome measures (PROMs) and person-reported experience measures (PREMs) as essential tools for enhancing patient-centred healthcare. As healthcare shifts focus from ‘what is the matter with patients’ to ‘what matters to patients’, PROMs and PREMs provide vital feedback on quality, patient engagement, and treatment outcomes. PROMs measure patients’ perceptions of their health and the effectiveness of interventions, while PREMs capture their experience of care. Their implementation supports shared decision-making, improves clinician-patient communication, and informs service improvement and health policy. Despite the potential, the integration of PROMs and PREMs into routine practice remains fragmented due to various behavioural, technical, and organisational barriers. This chapter outlines their role in monitoring healthcare performance, fostering personalised care, and achieving cost-effective, high-quality outcomes. By addressing these challenges, healthcare systems can reduce unnecessary costs, enhance patient satisfaction, and deliver measurable improvements aligned with the ‘Triple Aim’ of better care, better population health, and lower costs.