This study uses Conversation Analysis to investigate how doctors and patients talk about the duration of patients’ symptoms during acute general practice consultations in Denmark. Both parties treat it important to address and reach shared understanding about this issue, and it is the subject of much clarification and negotiation. Mentioning the duration of symptoms may be patient-initiated from the very outset of the consultation, as part of the problem presentation, or doctor-solicited in the subsequent interaction. Analysis reveals that in both cases, patients use concepts that stress relative duration as part of efforts to legitimise their visits. Legitimisation by such means is most evident in connection with doctor-solicited mention of duration of symptoms. Patients treat doctors’ questions as preferring an answer, which confirms that they have been sick for a long time. Overall, the study provides insight about the huge impact that discussions about time have for conversational organisation during consultations. It also shows how a shared understanding of the duration of symptoms is treated as a precondition for medical decisions and entitlements.