Devices, systems, and methods for detecting user devices to determine a state of a watched show are provided. A digital video recorder (DVR) is configured to store a media file associated with a media program. The DVR detects one or more user devices within a predetermined vicinity while the media program is being played. The DVR identifies users who are interested in the media program. The DVR tracks a watch status associated with the media program indicating which users have watched or are watching the media program based on the detected user devices. For stored media files, the DVR determines whether to delete the media file based on whether all users who are interested in the media program have completed watching the media program. The DVR may track user activity and/or vital signs based on sensor data from wearable devices, for example, to determine user reaction and/or user interests.