As smartphone notifications increase, so does the effort required to handle them effectively. Previous research has proposed various notification management features, but empirical evidence regarding their efficacy remains sparse. In response, we developed a notification management application incorporating features derived from prior studies, including both automatic and manual sorting, categorization, and manual pinning. Utilizing a mixed-methods approach, we explored how users interact with these features in their daily routines, with the aim to identify the underlying needs driving their usage. The results indicate that pinning was the most valued feature, serving diverse purposes such as deferring notifications, ensuring quick and constant access to information, preventing accidental deletions, and providing visual reminders. Conversely, manual categorization was underutilized, with participants relying on automated categories for notification access. Moreover, participants expressed a desire for automatic features to process and organize notifications based on topic and personalize them through user input. They also expected automatic sorting to adapt more dynamically to user contexts.