How does Tom's life change as a result of his ordeal on the ledge?

Tom changes because he realizes that that there are more important things in life than work. But what he really comes to understand is how desperately foolish he is. First of all, his decision to go out on the ledge to retrieve his notes is very stupid. Finney is very much concerned with recording the details of Tom's inner state out on the ledge, and mostly what Tom is thinking about is how to keep his balance. But it's also pretty clear that Tom regrets his decision to climb out his window. Not only is this decision foolish, but he comes to realize that his ambition—his project to develop new grocery store displays—is not very important either. There is a kind of arrogance in the importance Tom assigns to his notes, as well as in his obsession with his career. Even though he knows that this side project will not get him a promotion, he is still compelled to do it, and the thought of duplicating months of research is more than he can bear.
I think, in the end, what Tom realizes is that his love for his wife is more important than his personal ambition. It's not clear from the story that he has become any less self-centered: his motivation to find his wife at the movie theatre could be interpreted as having less to do with her than with his desire to add more pleasure to his life. The final bit, where the paper he endured so much to preserve flies out the broken window, is ironic: he laughs at his own foolishness.

"In the Contents of the Dead Man's Pockets" Tom Benecke has a revelation about the direction of his life and his misguided use of time.
Early in the story, Tom is focused on advancing his career at the expense of his relationship with his wife and his enjoyment of leisure activities. He spent most of his non-working hours doing research on an idea for making the grocery industry more efficient. Instead of balancing his work life with his home life, he put his relationship with his wife on hold, promising her things would be better when his idea came to fruition. His life was out of balance.
After his ordeal on the ledge, which represented a near death experience, Tom realized his transgression. As he hung on the ledge, he realized how insignificant his life was, and how important his wife was to him. Once off the ledge, he rushed off to be with his wife as she enjoyed a movie. This is symbolic of his new appreciation for life and relationships.