My iPhone 5s battery doesn't last?

My phone will be at 100% then within 30 minutes it will be at 20 then when I plug it it it says this accessory is not available a makes it stop charging I did drop it in water about a month ago but i put it in rice and it worked fine until about a week ago

Are there any accessories I should considering buying along with an iPhone 6+?

I'm 17 and am very likely getting the iPhone 6+ when I turn 18 next week. I was wondering if any users of the iPhone 6+ could answer the following question: Is there any accessories you would deem necessary in purchasing for this phone. Does the screen easily crack? Should I get a screen protector? Should I get a case? If you are knowledgeable enough to answer any of these questions please let me know your thoughts in a response below! Have a great day!

Why isn't my iPhone letting me download apps?

I've been trying to download some apps on my iPhone and it's not letting me for some reason. I tried restarting my phone and it still doesn't work. I'm not sure if it has anything to do with it but before this happened I updated my phone to IOS 8.4.