Please read this section FIRST. There are a great many misconceptions about how Android works with regard to
starting and stopping applications.
Android was designed from the ground up as an operating system (OS) for mobile devices. Its built-in application and memory-management systems were engineered with battery life as one of the most critical concerns.
The Android OS does not work like a desktop operating system. On a desktop OS, like Windows, Mac OS X, or Ubuntu Linux, the user is responsible for closing programs in order to keep a reasonable amount of memory available. On Android, this is not the case. The OS itself automatically removes programs from memory as memory is needed. The OS may also preload applications into memory which it thinks might soon be needed.
Having lots of available empty memory is not a good thing. It takes the same amount of power to hold "nothing" in memory as it does to hold actual data. So, like every other operating system in use today, Android does its best to keep as much important/likely-to-be-used information in memory as possible.
As such, using the task manager feature of SystemPanel to constantly clear memory by killing all apps is strongly NOT RECOMMENDED. This also applies to any other task killer / management program. Generally speaking, you should only "End" applications if you see one which is not working correctly. The "End All" feature can be used if your phone/device is performing poorly and you are uncertain of the cause.
The SystemPanel process listing groups applications into three categories: "Active", "Inactive", and "Internal":
The "End All" button, shown on the home screen of the application, is used to terminate all running tasks. Tapping the button will open a menu allowing you to choose the "severity" of the operation, e.g., whether only applications should be terminated or if all running processes should be stopped. Holding down the End All button will terminate all running applications, but will not attempt to terminate system-level processes.
The End All button should only be used when absolutely necessary. The most common scenario to warrant its use would be if your phone becomes very unresponsive and you are unable or do not have time to discern the cause. Using "End All" is a good idea when you otherwise think you might need to reboot your phone/device.
"End All" should NOT be used to free memory. Android will simply cache new applications into memory once it detects free memory is available. Such behavior is normal, will improve performance of the phone, and will not cause additional battery drain. Attempting to constantly use "End All" to keep memory free will however cause the phone to have to do more work (reloading applications), which can actually have a negative impact on your battery life.
You can specifically exclude critical processes from being terminated when pressing the "End All" button. To do so, tap the process item and then tap the "Exclude" button. A blue "Ex" label will then be present next to the processes name. This feature is beneficial in cases where you have important processes that you never want terminated even in the case where you have to use End All.
It's not important to use the exclusion feature, and in fact most users will likely find they don't want to exclude any applications, as the End All button should only be used in cases where the phone/device is fundamentally misbehaving.