He was not wrong in leaving the house. Tom was old enough, strong enough, healthy enough and fed up enough to make a man out of himself, and initiate a new life. He was, indeed, way past-due at Amanda's home. I can almost see myself in his position and I can guarantee you that I would have not lasted long.
Tom had a passion that he had not been able to feed. But, once you discover your passion, to deny it is the same as to extinguish it. Tom would have ended up in very bad steps if he had not at least tried to move way from the pressing environment of his home. Ultimately, Amanda, Laura, and every single human being is responsible for their own lives and for seeking their own happiness.
I don't think there is an easy answer to this question. Certainly, on the one hand, I think we can see from Tom's character that he regrets his decision to leave home inasmuch as he is abandoning his beloved sister. However, at the same time, his life at home was pretty much intolerable, with his mother who really didn't understand who he was or what he was trying to achieve. I don't think he could have survived much longer at home, so he definitely needed to get out, but I think that it is clear it is a choice that is going to haunt him for the rest of his life.
I think Tom did what he had to do to keep his sanity. Here's Amanda hawkishly watching and monitoring his every move and dollar. He is still living in her home, so he owes her respect; however, it's beating him down. He's working in a dead-end job and knows he has no chance for escape because his family is counting on him for their survival. He's taken it as long as he can, but he's finally got to follow his own dream and pursue that which he hopes will provide fulfillment. I don't admire him for it, but I don't blame him.
This is a great question for the discussion board since it is an opinion question.
I don't feel that Tom had another choice. He had to leave home before his mother drove him crazy. Tom felt completely oppressed at the apartment and hated even going home. He would go to the movies every night to escape. Ironic is that he used the fire escape to get in and out of the apartment, as well. Tom is the only one, in my opinion, who was capable of breaking away from the horribly depressing environment of the apartment with his mother and Laura. I believe Tom knew that he could never change Laura or his mother and make them see how they were acting, so he knew he had to leave in order to have any chance of having a "normal" life, so do I think he was right for leaving home? Yes, I do.
I think in the end he regrets that he had left his home and feels terrible gilt for abandoning his sister. So, I don't think it was a right decision for him.
It seems to me that only emotional connection he had was with his sister. If he cannot find peace in his new life because he is still caught up in the past, then he had became just like his mother. Perhaps he could have avoided that if he had tried to confront reality and help his mother and sister.
His escape looks like escape from reality to me (just like movies and alcohol). In my opinion he should have stayed and tried to work out his problems instead of running away like a coward.