This article reports the findings of a study on reasons for the placement and replacement of direct restorations in general dental practice in the United Kingdom. Twenty-two selected practitioners recorded information pertaining to up to 250 consecutive direct restorations placed by themselves during a 6-week period. From data derived from 2,379 restorations, it was found that about 60% of restorative practice in the United Kingdom may be found to comprise the replacement of existing restorations. For restorations of amalgam and glass-ionomer cement, the principal reason for replacement was secondary caries. For restorations of resin composite, secondary caries and poor appearance accounted for equal proportions of failures. Apart from the need for more extensive surveys of the type reported, the data emphasize the need to monitor treatment treands in contemporary clinical practice.