Sure...what do you do? leave it on sleep with battery saver on?

"Use it a lot" for what? Sounds like this needs to be defined, because, nope!

Haha. Even with light usage the S5 can hardly finish out a single day. I have one sitting in front of me right now.

I use mine like a phone

texting/calls maybe a map and the odd app music/playstation.

Email/web browsing why would you do that on a phone? use a computer.

Absolutely they do. Because one of the major issues that everyone faces with smartphones nowadays is the battery backup.

No, we turn our phones on and use them... emails, games, web browsing, video... even occasional use drains most* batteries quickly with current devices.

You are either:

a.) Not using your phone much
b.) Have a battery extending/rechargeable case
c.) Are pretending to have the only S5 in the world that magically lasts for "3-4 days" (based on your post above) under heavy usage

So... pick one, because, those are the only options that would make any sense.