Android beginner difference between padding and margin [duplicate]

I have referred questions on SO. ALso checked an answer:
Padding is the space inside the border, between the border and the actual view's content. Note that padding goes completely around the content: there is padding on the top, bottom, right and left sides (which can be independent).

Margins are the spaces outside the border, between the border and the other elements next to this view. In the image, the margin is the grey area outside the entire object. Note that, like the padding, the margin goes completely around the content: there are margins on the top, bottom, right, and left sides.

Also, more on padding and margins from:

http://developer.android.com/reference/android/view/View.html
http://developer.android.com/reference/android/view/ViewGroup.MarginLayoutParams.html

But what is the difference fundamentally between padding and margins ? Would the behaviour differ depending on O.S. and devices?
I have a normal, simple layout. No problem with code, have used layout folders - layout and layout-sw600dp plus drawables-4dpi. Can't make layout without margin or padding, which one is more appropriate?

Margin

Margins make up the vertical and horizontal areas between elements. If elements have no margins around them, they will bump right up against each other. In other words, he space outside of, or between, elements is what comprises the margin areas.

Padding

The padding of an element is the horizontal and vertical space that’s set around the content area of the targeted element. So padding is on the inside of a box, not the outside.

Padding is for inside/within components. Eg. TextView , Button, EditText etc.
Eg. space between the Text and Border

Margin is to be applied for the on-outside of the components.
Eg. space between left edge of the screen and border of your component

Visual representation is great in : Difference between a View's Padding and Margin

With Padding, i have seen a difference in 2.2, 2.3 and say 4.3, 4.4
in such cases:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:text="ASDFGHJKL" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingLeft="15dp"
        android:text="@string/hello_world" />

</RelativeLayout>  

Also, check the use of dimens:
http://developer.android.com/guide/topics/resources/more-resources.html

In Simple words .. if you want to take your widget like TextView, EditText far away from other. You should use margin from top,right,left,bottom.

By increasing padding it will increase the inner spacing not making the widget far apart from others..

Like buttons, for example, the characteristic button background image includes the padding, but not the margin. In other words, adding more padding makes the button look visually bigger, while adding more margin just makes the gap between the button and the next control wider.

Margin: Between border and its parent layout

Padding: Between content and border

refer to this

The difference between margin and padding and use cases are clearly explained by +Nick Butcher in Udacity's video. Here's the excerpt:

...if you want the touchable area or the background of the object to be enlarged, then use padding, otherwise use margin...