Although anaesthetic and surgical procedures should be individualised for every patient, in practice many preoperative protocols and routines are used generally. In this article, we aim to emphasise: why preoperative assessment is important; how it should be done, and by whom; what can be expected; and the importance of test selection based on patients' needs and on scientific evidence of effectiveness. We outline the roles of preoperative medical assessment in otherwise healthy patients. Clinical history, preoperative questionnaires, physical examination, routine tests, individual risk-assessment, and fasting policies are investigated by review of published work. Cost of routine preoperative assessment, the anaesthetist's legal responsibility, and patients'views in the preoperative process are also considered. A thorough clinical preoperative assessment of the patient is more important than routine preoperative tests, which should be requested only when justified by clinical indications. Moreover, this practice eliminates unnecessary cost without compromising the safety and quality of care. Education and training of medical doctors should be more scientifically guided, emphasising the relevance of effectiveness, and cost-effectiveness in clinical decision-making and complemented by audit.