The above answer is excellent. It might also be added that Roma should learn to save his money for old age, or for a rainy day, or both. Like a lot of salesmen, Roma seems to have an attitude of "Easy come, easy go." He spends a lot of money on liquor and eats his meals in restaurants. If he doesn't win that new Cadillac he will have to spend a lot of money on transportation. He may think the good times will never end, and that a salesman can always make money by finding something the public wants. Shelly Levene undoubtedly thought the same when he was young and was making piles of money.
David Mamet's play Glengarry Glen Ross is perhaps the closest examination of the life of salesmen since Death of a Salesman. The aging Levene is in despair throughout the narrative, while Roma seems to be calm and in control of his situation. Roma sits at the top of the sales board, exactly the position Levene did many years before. Levene can't procure any good leads, ends up stealing new leads from the office, and is caught when he gives himself away. Roma should be able to look at how far Levene has fallen and see that his future can and probably would end up the same. The life a salesman leads is nice, as long as he is making sales. The minute Roma loses his touch, gets a string of bad leads, or drops a huge sale (as happens in the play), he will be standing in Levene's shoes glancing across the room at a young lion who has taken his place.