If modern clinical techniques were carefully followed, many common endodontic problems would never occur. Incorrectly designed access cavities may make root canals both difficult to identify and to instrument. Careful study of the pre-operative radiograph is essential. Various aids are available to remove fractured instruments and failed root fillings, but the problem must first be correctly diagnosed. As more patients seek cosmetic procedures, the practitioner should be familiar with the 'walking bleach' procedure, again after careful diagnosis of the cause of the discolouration. The practitioner should also be fully aware of the prognosis for this and other endodontic procedures.