Is Closing iPhone Apps Good or Bad? 

 
One of the main reason why others recommend closing out your apps is to prevent your battery from draining when an app doesn’t enter the background state or suspended state the way it should. 

But there were those iPhone users who were against about closing apps: 

It takes more power to open an app from the not running state than it does to resume it from the background or suspended state. This is absolutely true. 

Apple puts a lot of effort into making sure the iPhone operating system manages memory efficiently, which minimizes the amount of battery apps use when they remain in the background or suspended state. This is also true. 

You are wasting battery life if you close out your apps because it takes more power to open iPhone apps from scratch than the operating system uses to resume them from the background and suspended state. Sometimes true. 

But contrary to those mention above, there were also various reasons why it is said that closing an app is a good idea: 

Even if you close your apps every time you use them, you will not see a difference in battery life because the amount of power it takes to open an app is insignificant compared to the amount of power it takes to use the app. 

Apps that stay running in background mode continue using power when you’re not using your iPhone, and that adds up over the course of a day. 

Closing out your apps is a good way to prevent serious software problems that can cause your iPhone battery to drain very quickly. 

 

There were other reasons on why should or shouldn't apps to be closed. I guess it's up for the individual users to dwell on it.