Odds of Hanging On
There are over a hundred guys on the men's PGA Tour, another handful or so who can make money on other tours—and that's it. The same numbers are true for the women's tours (although the money is about a third of the men's pay—or worse). This all means there aren't a whole lot of spots on tour, so to maintain a spot you really have to prove you belong there.
Basically, get the ball in the hole. We can't stress this part enough.