A question that often comes with Google's Android operating system is whether or not you need a task manager/killer. Android was designed to handle processes efficiently and should not require a task manager. However, badly coded applications from the Android Market create the need for task killers.
Android Resource Management
The Android operating system designed by Google is a slimmed down version of Linux and GNU software. It may appear that many applications are running in the background using up resources on your phone, when in fact they aren't using any resources at all and are simply waiting in a ready state. Android will automatically dispose of processes that have been sitting in a ready state and have not been used in a long period of time. Using a task killing application may actually slow the phone down as it will automatically relaunch processes that it feels it needs to run almost immediately after you close them with the task killer. It is best to let the Android operating system do what it was designed to do, run efficiently. Android does not handle memory like Windows operating systems. Potentially, memory usage could be at 100% and still be getting used efficiently. Since each application runs in its own process, Android will stop and start them as needed.
When Task Killers are Useful
The Android Market place is open to anyone who can write a few lines of code and submit their applications for users to download. Because of this, you may find a task killing application to be useful. A third party application that has poorly written code may not be handled the way Android resource management was intended, resulting in an application hang or process that cannot be killed or made available for other applications. With the use of a task killing application, you can simply kill the task to release the process. If you are an Android application developer, a task killer may be of value to you as your application goes through testing and debug phases.
Should You Use a Task Killer?
Whether or not you should use a task killing application on your Android phone is ultimately up to you. You may install one and have increased battery life and a faster phone. On the other hand you may install a task killer and not notice any difference. You will have to try one and find out for yourself. I use Advanced Task Killer on occasion as I regularly download applications from the Market Place and have run across some that were poorly coded. It has come in handy a few times, but for the most part I just let Android do what it was designed to do.
According to Google you should not need a task killing application on your Android phone. It was designed to run efficiently right out of the box. However, with an open market place that has thousands of applications available with no quality control, you may find a task manager useful. If you are not sure which task manager is best, you can read my article, "What is the Best Task Manager for Android?".