Came across good article which brief about why we need to stop using app killer in Android.
Brief from Artile
Your resistance is futile. I mean, it’s not like Android will keep opening apps in the background until you’re completely out of RAM. That would cause your phone to completely freeze and lock up and wouldn’t make any sense. Android is smarter than that. Instead, it will begin closing the oldest apps still open in the background to make space for new ones. I mean think about it, do you have to manage the RAM on your home computer? No. It just works, right? Same with Android.
Android PSA: Stop Using Task Killer Apps – NOW
Brief from Artile
Your resistance is futile. I mean, it’s not like Android will keep opening apps in the background until you’re completely out of RAM. That would cause your phone to completely freeze and lock up and wouldn’t make any sense. Android is smarter than that. Instead, it will begin closing the oldest apps still open in the background to make space for new ones. I mean think about it, do you have to manage the RAM on your home computer? No. It just works, right? Same with Android.
Android PSA: Stop Using Task Killer Apps – NOW