What is the last event that sets management properties?

In today's interview, I asked what is the last event in the page life cycle where you can set management properties. I said that this will be an event (for example, a button press, etc.), or if there is no event, then set it to the page load event. Then he said that I need the name of the last event. Can you tell me what is the last event to update management properties and why can I use such an event? rather than loading a page or clicking a button, etc.?

Thanks in advance:)