What are some of the key events that extremely impact Montag and make him such a dynamic character throughout the novel?

There are many events and plot points in Fahrenheit 451 that impact Montag significantly and force him to change. As the novel begins, Montag is an ordinary fireman who mindlessly burns piles of books because he is told to, but that all starts to change when he meets Clarisse, the strange girl next door. A quirky and intellectual young woman, Clarisse questions Montag's beliefs and prompts him to question them himself. They have frequent conversations—and Montag looks forward to these—about many taboo and philosophical subjects. Montag begins to feel intellectual—and, perhaps, romantic—longing for her, and when she disappears, he begins to feel disillusioned with his life.
Another key event that impacts Montag is his wife's suicide attempt. After she wakes up from her sleep caused by the plethora of sleeping pills, she seems to completely deny having tried to kill herself. Her apparent unhappiness makes Montag uneasy, and he then begins to question the foundation of their marriage and, consequently, their life.
One final key event that shapes Montag's character is the suicide of the woman whose house full of books is to be burned. In a defiant act against the firemen and society as a whole, the woman lights herself on fire and goes up in flames along with her books. This causes Montag to further question the value of the books, for if someone was willing to die alongside them, doesn't that suggest them to be entirely invaluable?