used when the person or people being spoken to both cause and are affected by an action

used to emphasize the fact that the person who is being spoken to is doing something

Do it yourself—I don't have time.

You can try it out for yourselves.

You yourself are one of the chief offenders.

used instead of ‘you’ in order to sound polite or formal (although some people do not consider this use to be correct)

We sell a lot of these to people like yourself.

‘And yourself,’ he replied, ‘How are you?’

LEARNit Dictionary