1. Match occurrence : Use when want dependency of the same number of occurrence of the depended Job.
2. Last occurrence : Use when want your dependent job should not be bother the same occurrence of depended Job.
3. First occurrence : Use when you want to always consider first occurrence of depended job.
The choice of above dependency is based on you need. Generally if you are going to schedule your Jobs and scheduled job using dependency or output coming from depended job into dependent job then this matters.