9. There Are No Support Groups
Clay Tumey did not tell anyone in the world that he was robbing banks while he was doing it. This turned out to be one of the keys to him never getting caught. No one can rat him out if literally no one knows what he's doing.
"I never told anyone what I was doing. One of the main things I learned from research was that an overwhelming number of people are caught because they didn't do it solo. So I never let anyone (not even my wife or best friend) know what I was doing."
And to reiterate the circumstance of his prison stay: he turned himself in. If he had chosen to keep his criminal activity to himself he might not have ever done any time.