Replacing an Iphone 5c battery?

For the past few months my phones been dying at 15 percent and recently as high as 28 percent. I've noticed that it's battery life has also been getting shorter. I used to be able to go 2 days without charging, and now I find I have to charge it twice a day. I've had my phone for about 2 or 3 years so I'm not sure if this is a normal thing or not. I'm thinking the battery needs to be replace.
I originally got my phone from Verizon but it's an apple so does it matter what store I go to to get it fixed? Which would charge less? I've seen relatively cheap kits to do it yourself, but I'd probably just ruin my phone instead. Would I be better off replacing my phone? Replacing is honestly the last thing I want to do, call me overly attached, but if a new battery cost the equivalent of a new phone then I might as well replace the entire phone.

IPhone search bar 'TOP HITS'?

Whe you pull down the screen on your iPhone, search an app and it says that app is under 'TOP HITS' does it mean they personally use that app a lot or does it just mean it's generally a 'TOP HIT' on iPhone users? And what about if it's an app they deleted ages ago, but it still comes up under their top hit?

What should I do if my iPhone gets stolen?

Someone stole my iPhone and it's off and find my iPhone is off. It's been 3 days now. How do I get a new phone? Do I have to pay for another one? I can pay for a new phone I just got this phone.

Why is my cellular data on sprint all of a sudden so slow?

My mom, my sister and I, all have an iPhone 6 on sprint. All three of us usually get a good LTE signal rarely dropping to 3g (but sometimes it does) when we're at home. And my dad has an iPhone 5c and same thing for him. But today all of our iPhone 6 can't get lte for even one second. But I looked at my dads phone and he has a strong lte signal constantly and I did a speed test on his iPhone 5c and got ping of 50ms, download 13mbps, and upload 3mbps. His Ping is better than what I get on my phone even on lte at my house. Why are the iPhone 6 being slow?

My iPhone sound is not working?

So when I try to call someone I have to have my phone on speaker other wise I can't hear the person on the other end talking or even hear the ringing, my phone is not on silent and the sound is on high along with it not saying that my headphones are in.

How to access iPhone contacts with a broken screen?

My phone screen is blank black and unresponsive. It's been like that for a few days so today I went and got an iPhone 6 because it was time for a new phone anyways. I would like to get my contacts off my old phone if possible.
I didn't back up my information to iCloud, so that's not an option. I tried plugging it in to do it via iTunes, but in order for iTunes to do that I need to authorize access to it on my phone… Which I can't do because my screen is unresponsive. Does anyone know a way around this?

Can I get my photos from my old iPhone?

I've taken some photos on my old iPhone 5, in which I factory reset due to selling it. Now I have an iPhone 6, can I access those photos from iCloud or something?