Most of the PCAOB's provisions and powers have been well received especially due to auditing failures like Enron, with the exception of mandatory audit firm rotation. Audit firm rotation is a provision that requires a firm to change auditors every certain period of time in hopes of discouraging long-term relationships that could potentially interfere with an auditor's independence. Common opinions on this specific clause hold that the costs related to this measure would outweigh its benefits. Ultimately, no two companies are the same; they may resemble each other but each is its own. The fundamental objective of an audit is to obtain a truly independent opinion for all those who rely on the financial statement. For an auditor to familiarize themselves with the company a lot of research needs to be done and this takes time. According to a survey conducted by the General Accounting Office, the average tenure of an auditor who is believed to interfere and increase quality and independence risk is twenty-two years. (GAO) With an imposed mandatory rotation clause, auditors would have a very difficult time acquiring the knowledge needed to attest to such truly impartial activity