OP: First off, do not listen to these ignorant people who will tell you to upgrade. I am glad you are still on iOS 6. That reflects that people are still using it and not upgrading to the crap that iOS 8 is. I bet you anything your iPhone 5 performs better than the iPhone 6/6+ in terms of fluidity. Your iPhone 5 will also get the best battery life on iOS 6.1.4. DO NOT UPGRADE IT. Your battery usage will go drastically down. iOS 8, yet alone 8.4 performs like crap on the iPhone 5. It's laggy and animations stutter almost all the time.
Keep your phone on 6.1.4 for as long as you can. You will gain nothing by upgrading it, except a childish inspired OS full of horrible whites and abysmal icons. It will make your phone worse. Btw, your battery usage looks great.
I wouldn't necessarily say thats true. My iPhone 5 is on iOS 8.4 and it performs very well. While iOS 8 is a pretty terrible OS, the 5 definitely handles it pretty well, with very minimal slow downs from iOS 7. The only time it really lags is when you first unlock it after turning it off. The OS that is right for an iPhone 5 all depends on what you like. iOS 8 is a great OS, but I understand people not liking the iOS 7 and above 'Look', but that doesn't make it a terrible operating system.
Nobody is ignorant here. In security terms its a terrible idea to run iOS 6.1.4, and also in terms of app compatibility. If iOS 6.1.4 is what works for the OP, so be it, but nobody is ignorant for suggesting upgrades.