I have iphone 6s It's operating the newest iOS (10.3.3) and is fresh out the box. I am not a heavy user or have any fancy apps but my battery can barely make it through my work day and commute. Not sure why. My iPhone 5s of 3 years lasted much longer even.

I checked the battery feature is setting and there's not too much surprises in terms of usage, it's just they burn through data faster than I've ever seen.

Any tips? Do I have a faulty battery? Should I visit Apple store? Is repairing costly? As I am in Hawaii my friends suggested me to visit repairing stores like TCAWireless and few others. Should I visit? I am confused. Please help.