How do historians use turning points to better orginize information about the past

They may base events from history on periods of time using a certain theme, so to say. This way, it allows them to organize information in a chronological order and base events on how severe they were and what led up to the most significant event in that time period, because a turning point is basically the most important part in a time period which initiated change. This also emphasizes on the importance of transitions.