Can people access my location because of my iphone?

I don't currently own an iphone, but I'm looking into it once the new iphone 5s comes out.

I'm trying to decide what to do, because I'm incredibly uncomfortable with the possibility that people could see where I have been. I'm not talking about apple itself, but just anyone who wanted to see (like a psychopath! )
I read an article which made me think about this, so I'm curious as to what everyone thinks/knows.

this was the article: http://www.csmonitor.com/Science/2013/0513/Can-your-iPhone-s-digital-footprints-reveal-your-physical-location

Please help me! I don't want people being able to find my house or follow me places!

Added (1). Thank you!

How would someone find out my apple id/password?
Sorry! I seriously still have a flip phone and I'm quite the novice at smartphones: P

I'm I previous owner of an iphone, and I know that all apps will ask before they can use your location and If anyone else know your apple id and password they can track your iphone by using the icloud.com website which helps you find your phone if you have lost it.

You can check if a app uses your location bu going to "settings - privacy - location services" and if the app says "on" it uses your location, however if an app is currently using your location, in the top right-hand corner you would see a purple arrow.