My sister and brother-in-law just upgraded from their old feature phones to new Android smartphones. Luckily (and unlike a lot of friends and family who ask for my advice), they listened to me and went with a phone that would truly make them happy, not just their wallets. They made quite a big jump, so the questions began rolling in as soon as I met with them and our real life "Where's Waldo" adventure ended. During my layman's break-down of Android, rooting and all other aspects of the platform the conversation took a turn that sort of struck a nerve.
Upon buying your new phone, sometimes the carrier representative that has been helping you will try to give you a quick run-down and explain some things for you. Or maybe you have consulted a friend who has been behind the driver's seat with an Android smartphone before for some advice. Nine (maybe even ten) times out of ten, the rep or friend will suggest you install a task manager or "killer" (as they are often referred to) to help with both smoothness of performance of the phone and battery life. (Even I was guilty of this at one time, but have since been corrected thanks to our awesome readers.)
The truth is, these task managers and Android work against each other. Task killers are redundant, unnecessary and typically cause more harm than good. Yes, this goes against all that you have been told as an Android user; they seem like they're helping. This is called a placebo effect. So why are these app managers bad? How do they actually cause harm?
Unlike a PC where you must manage memory yourself by closing programs, the Android OS (2.2 and above) is meant to manage memory and processes on its own. Let's say the user launches an application. This app will then stay in memory until it absolutely needs to be closed. This is done to improve application launch time; the app will "run" in the background – leaving battery and performance essentially unaffected – ready to be launched again at any moment.
If a previously launched application is kept in memory, launching it again at a later time will take much less time. Killing the app removes it from memory and will slow down the application launch next time you need it. Android will automatically begin closing applications as needed, starting with the ones that have been inactive for the longest.
Most of these dreaded task manager applications come with a “kill all” or “autokill” feature. Why is this bad? I don't think I can explain it any better than Whitson Gordon of Lifehacker:
"... it's actually possible that this will worsen your phone's performance and battery life. Whether you're manually killing apps all the time or telling the task killer to aggressively remove apps from your memory, you're actually using CPU cycles when you otherwise wouldn't—killing apps that aren't doing anything in the first place.
In fact, some of the processes related to those apps will actually start right back up, further draining your CPU. If they don't, killing those processes can cause other sorts of problems—alarms don't go off, you don't receive text messages, or other related apps may force close without warning. All in all, you're usually better off letting your phone work as intended—especially if you're more of a casual user."
Now that we have that out of the way, how can these pesky task managers be of use? Well, in the case of a rogue app that, unbeknownst to you, is eating away at your CPU, you can kill the app using a task manager. Then again, the "force stop" feature is built into Android itself, effectively making any third-party task managers pointless.
Also, how would you know if an application is poorly coded or has gone rogue? Not all task killers are alike. More importantly, not all of them are bad. For instance, the popular application Watchdog monitors CPU (instead of RAM) and will alert you if an app is acting up. You can then take further action to stop the runaway app. If an app shows up once or twice in Watchdog, it's probably a fluke. If it shows up constantly or several times, try uninstalling to see if there is a change in performance or battery life. Like Gordon said, "If an app is causing problems on your phone, you're probably better off without it."
Since the introduction of Froyo, these task killers have secretly been plaguing Android users, stealing from performance, battery and sanity. Please spread the word and help out any fellow Androidian you may encounter that still uses a dreaded task manager app. And for the love of God, next time you are in a carrier store and a rep suggests installing "Deluxe App Destroyer 3000," correct them and explain to them that you would actually like to improve your phone's performance, not kill it.