In general, apps inside Android OS won’t need an Exit button. There is a life cycle for every applications where you have certain automatic exit and return or re-entry points. If an application is done well, there is no need for an explicit button, actually that is the main reason why Android apps usually don’t own a Exit button inside.
However, the fastest method we use to close an application is pressing the Home button, which doesn’t really “Exit” the app, it just minimizes it. That means it will continue to run in the background, even if you open another application. Happens that after you open some applications in a session, you may notice your device lagging a bit due to the number of opened applications, which are constantly using your device’s RAM. Maybe it’s not a problem on newer highly-specced devices, however this leads in chewing away precious battery life.
So, how to kill background applications that you’re no longer using.
1. Launch the recent application’s menu.
Getting access to this menu varies from device to device. On Samsung Galaxy S4 tap the physical button, on HTC One tap the home button twice, on Nexus 5 an on-screen button takes you to this location, on Galaxy S Mini press and hold the Home button then open Task Manager.
2. Close the applications.
There is no way to close all applications with one touch, so you’ll need to close them one by one, tap and hold the application then swipe to the right, this should kill the process from running and free up some RAM.
On Galaxy S Mini, to close all active app’s press End all, to close a specific app find it by scrolling up from the bottom and press the End button beside it.
Want to free even more RAM memory on Android devices?
If your phone’s still running slow, in Galaxy S Mini’s Task Manager there is a useful RAM manager, access it and press Clear memory, this should close some apps that are actively using RAM memory.
Newer Android versions doesn’t have a RAM manager included, other’s doesn’t even have a Task Manager, however you can download one from Google Market, or you can free some more RAM memory by Force Closing some useless Apps
Navigate to the Apps tab in Settings (on some devices Application Manager), select Running tab, press on any unused Application and tap Force Stop to kill the process for Good.