In one of the sequels to his LIttle Red Book (I forget which, but I think the cover was blue), Harvey Penick relates a conversation that his son, Tinsley, had with a 43-year-old amateur golfer from California who traveled to Austin Country Club. This man's goal was to play the senior tour, and he was going to sell his company and devote his life to golf. And he wanted the younger Penick to be his mentor for the next seven years, until he turned 50.
In reply, Tinsley told the man of another 43-year-old who was in a similar situation. And this Californian would have to play better than this other fellow if he was going to play the Senior Tour. And with that, the man pointed to Austin Country Club member Tom Kite.