componentWillMount

• App configuration in the root component
• Can call setState - but calling setState on a non-rendered component doesn't make sense

componentDidMount

• Ajax calls
• setState can be called here

componentWillReceiveProps

• Perhaps the Ajax call initiated by the parent's componentDidMount got resolved and a stream of new properties arrived at the component
• Here we have access to component nextProps and currentProps
• Do auxiliary stuff from the new property
• setState can be called here

shouldComponentUpdate

• get access to next prop and next state
• compare it with current prop and state to return boolean
• do not call setState here

componentWillUpdate

• Not used that much
• No access to next props
• Use componentWillReceiveProps

componentDidUpdate

• Updating the DOM in response to prop and state changes
• setState can be called

componentWillUnmount

• final cleanup
• setState can't be called