There is no easy answer for this.  There is initial material.  If you do a workshop, it is usually covered in a single day.  If you do private sessions, it usually takes 2-3 2-3 hour sessions.  This is to get through the critical material.  However, it is only the start.  The key is to stay faithful and incorporate the ideas and techniques into your own running.  Eventually, “chi-moments” occur and things start to click.  This is a clue to continue…to keep at it…to work more to develop the techniques.  The key is to continue to evaluate what is happening and how the body feels.  Be mindful.  The practice of ChiRunning is very much dependent on the idea of gradual progress.  You don’t go from being a non-ChiRunner to a ChiRunner in a certain amount of time.  There is no graduation.  It’s a process.  Changes in speed, endurance, or injury prevention happen over time and differ from person to person.  What is primary is to STICK WITH IT.  Those who have, report dramatic change not only in their running, but in other aspects of life as well.  Some people see changes in a few months, other continue to improve years down the road.