The study analyzes the influence of the maintenance of listeners with a single client on the independence and quality of the ISO 14001 audits. Based on a qualitative approach, it is conducted among 36 professionals involved in the process of ISO 14001 in Canada. The results indicate an absence of formal rules on auditor rotation that leaves the client’s will dominate over their maintenance. In addition, learning and understanding the customer’s system and induce various motivations remain the focus of two opposing influences of auditor tenure. On the one hand, it is considered essential for the auditor independence, effectiveness and efficiency of the audit and continuous improvement of the EMS. On the other hand, risks of familiarity with the client and the EMS remain and affect the rigor, objectivity and critical thinking of the listener. Finally, the study offers several possible solutions including the definition of formal rules of rotation of auditors after six years with the same client.