The embodiments set forth techniques for managing storage space in user devices. A storage space manager can be configured to receive a request to increase an available amount of storage space within the user device, identify applications where at least a portion of the application's associated data can be deleted to increase the available storage space, determining particular applications whose identified associated data should be deleted, and causing the associated data to be deleted. According to some embodiments, applications managed by the storage space manager are not adapted to manage storage space themselves. Instead, these applications can be registered to the storage space manager and can be grouped into subsets that share sections of storage space within the user device. Moreover, the storage space manager can be a subsystem storage space manager that interfaces with a higher-level system storage manager that orchestrates storage space management within the user device.