An audit is an independent examination of all the financial information, transactions and source documents of any business for a specific period of time (usually 12 months / financial year), regardless of its size or legal status. During such an examination, a registered auditor expresses an independent opinion on the company's performance. It results in the drafting and finalisation of annual financial statements intended to ensure that the books of accounts are properly kept by the company. The exercise is usually done once a year by a company and could take 2-8 weeks, depending on the size and volume of transactions. Annual Auditing and Drafting of Annual Financial Statements are usually part of a once-off engagement between the Client and the Auditor.