Task killers are useful under certain circumstances:

- When many apps have been installed, tens or hundreds. There may be tens of apps competing for the same resources, slowing down the device.

- When the Operating System (OS) does not prioritize the most important apps for the user . The current app, which has control of the screen, should have priority over all other active apps. Sometimes the OS does not schedule the processes properly, failing to prioritize the current task, which could depend on multiple processes. Sometimes even the real-time scheduling is deficient, which can cause the abnormal reproduction of audio or video.

- When it is necessary to control an app that is suspicious or does not behave well. Apps that consume too much CPU, memory or other resources are an example.