Multitasking on the iPhone appeared back in iOS 4, but back then everything was not so convenient. To close the application, you had to hold your finger on the icon, wait until the minus sign appeared, and only then close it. It was a little annoying. In iOS 7, everything became much easier – just swipe the application up, and that's it, closed. But many people started closing all applications on their iPhone several times a day, thinking that this way the battery will last longer. In fact, it even harms it.
What you should know
The system works so that when you minimize the application, iOS gives it a few seconds to complete the necessary processes, and then simply freezes it. If the application needs to update something – location or data, the system will do it automatically without your participation. It all works so fast that you don't even notice. And that's why constantly closing applications makes no sense. Not only do you not save battery, but you also spend more energy restarting these applications. So really, there's no need to bother.
But there is one situation when force closing can still help – if the application is frozen. This happens, especially with older phones, when they don't work so fast anymore. Then you can simply swipe the application up through the multitasking panel, and the problem will disappear. You open the application again – everything works as it should.
As for background updates, I turned this thing off a long time ago, because it really eats up the battery. And I didn't notice any acceleration in launching applications, even when I tried to measure it. So just turn off background updates and there will be no problems. Telegram and other apps will still open quickly, so don't worry. And by the way, don't close all apps anymore because of multitasking. The system will do everything itself, and the battery will last longer.