Mobile app redownloads of existing files typically stem from caching behavior or synchronization settings. Unlike desktop software that might reliably reference local copies, mobile apps frequently re-fetch remote content to ensure it's current. This happens because apps prioritize retrieving the latest version from the server over relying on potentially stale local files. Cache expiration settings or bugs in the app's local storage management can also trigger unnecessary downloads, even if the content hasn't changed.

For example, streaming apps might redownload temporary media files if their cache reaches a size limit or after an app restart. Social media apps often redownload image and video content displayed in your feed to fetch potential minor updates or new ad creatives. This is common across various platforms like iOS and Android when apps prioritize content freshness over minimizing bandwidth use.

While rechecking servers ensures users get the most current data, constant redownloads waste mobile data, drain batteries, and frustrate users. Ethical concerns arise regarding unnecessary data consumption, especially on limited plans. Future development focuses on smarter caching algorithms, background sync optimizations like Android's WorkManager or iOS Background Tasks, and user controls to limit data usage per app, balancing freshness with efficiency.