What is a common troubleshooting step for improving app performance on a device?

Clearing the app's cache is a common troubleshooting step for improving app performance because it helps to free up space and remove temporary files that can accumulate over time. Apps store cache data to help them load content more quickly, but as this data builds up, it can lead to performance issues such as sluggishness or crashes. By clearing the cache, you allow the app to rebuild this data more efficiently, often resulting in improved performance and responsiveness.

The other options, while they may have their own relevance or use cases, don't directly address app performance in the same way. Increasing the device's storage capacity could be beneficial, but it is not an immediate solution for an app that is currently underperforming. Similarly, turning on airplane mode doesn't relate to app performance, as it simply disables network connections. Resetting the entire system is a more drastic step, which may resolve underlying issues but is not specifically targeted at the performance of a single app.