Ethical behavior and auditor independence are pillars of quality external audit. How long an auditor can continuously audit his client's financial statements is a question that has been debated for many years by the auditing profession, especially regulators. Those who advocate the mandatory rotation of auditors believe that longer mandates of auditors reduce the quality of external audits. Such positions are based, due to the increasingly long time intervals of audit engagements, on the auditor 's increasing dependence on the client whose financial statements are being audited. Multiannual engagements of auditors with the same client are a suitable framework for the greater financial interests of the auditors, which inevitably put their independence, and thus quality of the work performed, to the test. Frequent corporate scandals for a reason repeatedly raise the question of trust in the auditing profession. In this regard, the need for a faster rotation of auditors emerges, among other things, as an effective measure to ensure auditor independence and audit quality. The rotation of auditors and the desired time frame for client retention are influenced by numerous factors, among which, for the purposes of this research, are analyzed: indebtedness, classification of the audit firm in the "Big Four", return on assets and opinion of the independent auditor. In this context, an appropriate research model was designed and tested on companies based in the Republic of Croatia that are listed on the Zagreb Stock Exchange.