When you go mobile the biggest thing you should limit is who knows where you are.

Location:

One thing that can be missed easily is that the Facebook app uses and publishes a rough approximation of your location on every post.

To prevent this you have to click the Location icon.

Then you need to click the little cross in the bottom right. When you review the draft you’ll see the approximation has been removed.

Disabling Locations:

Of course on iOS (iPhone, iPad) you can easily disable all location services for Facebook App.
On the devices Settings, go to Location Services.

Scroll down and turn off Facebook.

However, if you try to use the usual Check In function though, you’ll be prompted to turn this back on.