In scenarios where a dropdown list needs to dynamically reflect data that could change over time, such as a list of laptop models maintained in an external system, using a data page is the best approach. Data pages in Pega are designed to retrieve and cache data from various sources, including external systems. They are ideal for scenarios where data needs to be up-to-date and reflected in UI elements like dropdown lists. Data pages can be configured to refresh as needed, ensuring that the dropdown always displays the current set of available models.