The main reasons for using so much data are background app activity, automatic updates, and high-quality streaming. Apps often sync and refresh content or download updates automatically over mobile data rather than Wi-Fi, leading to data spikes. Streaming videos in HD or higher quality, auto-playing social media content, cloud backups, and location services also consume large amounts of data. Additionally, VPN use and unexpected background processes can increase data consumption. To reduce data usage, it is recommended to turn off background data for non-essential apps, disable automatic updates on mobile data, lower video streaming quality, use Wi-Fi whenever possible, and monitor which apps use the most data through phone settings.