Q: Battery bad 5s ios 9.3.4

Howdy Pollarline!

Being able to use your iPhone without the battery dying quickly is certainly what we'd expect out of an iPhone.  Since it seems like yours is dying more quickly than normal, we certainly can take a look at some steps to do so that you can get the most out of it.  

Take a look at this article since it'll give us an idea of what application or process is using the most battery life: About the battery usage on your iPhone, iPad, and iPod touch

Also, this article here will give some helpful tips to maximizing the battery life on your iPhone: Maximizing Battery Life and Lifespan

If you're still experiencing issues after going through both of those articles, we would need to see about isolating the issue so that we can find out if it's a hardware or software issue.  To do that, we'd need to create a backup of the iPhone and then restore it to factory settings like a new device.  That will tell us for sure if it's hardware or software related.  Take a gander at these two articles which will tell you how to back up and the restore the device to new:

How to back up your iPhone, iPad, and iPod touch

Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings

Make it an awesome week!