Major astronomical discoveries of the past have been closely linked with the implementation of strikingly powerful new observational techniques in astronomy. Surveys, in general, were not as likely to lead to the discovery of new phenomena. In recent years, however, many far-reaching instrumental advances have been incorporated into observatories in space, whose mission, in part, was to conduct unbiased surveys. Here, we provide a review of some of the successes of earlier surveys, with the purpose of identifying the relative extent to which increased instrumental capabilities, as contrasted to increased sky coverage or numbers of sources observed, may be expected to lead to the discovery of new phenomena. A similar comparison can be made of the extent to which these two approaches—emphasis on instrumental capabilities, as contrasted to emphasis on sky coverage— also contribute to an increase in astrophysical understanding. Here, the distinction needs to be made between discovering a new phenomenon and understanding its underlying processes.