How long was violet been chewing her piece of gum Charlie and the Chocolate Factory?

In "Charlie and the Chocolate Factory," Violet Beauregarde is chewing her piece of gum for about three months before she enters Willy Wonka's factory. She is obsessed with gum and has been chewing it continuously, which ultimately leads to her transformation into a giant blueberry after trying an experimental flavor. Her determination and disregard for the consequences illustrate her character's flaws.