The Nunn Center’s general rule is approximately 5 minutes, however this varies based on the level of indexing you have chosen as well as the content of the interview itself. Sometimes a segment has a clear topic and a clear beginning and ending, whether that ending is at 3 minutes or 9 minutes. It is more important to create segments based upon their content than based on their length. However if a topic is only touched on for a minute or so it is best to include it with the segment before or after. Likewise if a segment is over 10 minutes you may want to consider breaking it up based on subtopics if possible.