Good Enough

This is a quick concept that has been moving through my head for the last few months. When does a person say "no" to an internship and "yes" to something else? Is there a standard formula that is used to determine when and how a person is eligible to ride without the training wheels? Is a person considered superior when placed into a position of great responsibility and or commitment? I wish I knew...for I feel that I am going to end up at the starting line again. When is a person "good enough" to fly solo in ministry?