I am using an iPhone 5 with the iOS 6.1.4 and usually it will get notifications to update the iOS. What are major differences between these two and WHAT ARE BENEFITS OF RETAINING THE 6.1.4 AND THE BENEFITS OF UPDATING TO 8.2? My dad is using the same phone as me however, he is experiencing battery shutdowns quite often and he using iOS 8.2 I would like to know whether retaining my iOS without updating is good? or is it better for me to update to 8.2? I would like to listen to good experience and knowledge before I proceed further.
Neither is better nor worse. Each has their strong-points and uses in the industry.
iOS 6.x, although having less features, requires a less powerful device to run on. iOS 8.x will require a more up to date device to run on.
More than often, I see iOS 6 and 7 still used in businesses on internal devices. As a personal device, I'd personally say move to iOS 8.
If your device is on iOS6, although many of the "newer" applications won't run on it, the App Store is designed in such a way to filter applications that will ONLY run on the platforms that your device supports. ergo, if you're on iOS6.x, the App Store will list iOS6 and lower applications...
8.x is aimed at eye candy as well as "handy functionality", by this I mean you have interesting features such as the "health kit" which constantly measures your steps in a day, the height you walked up and down in a day etc... to get a general idea of your health regime.
So it's entirely up to you which you'd prefer to stay on. Do note that apple no longer support various devices (they call it EOL - end of life) and with that comes the operating systems they were designed for! So do read into the T's and C's of whichever OS you're going to sit on and make sure that :
1) Apple will support it 2) Your Apple Cover Plan will cover it
Hope this helps.