he hasn't always been prudent in all situations, but it is a characteristic he's possessed for a long time. Then, the manner in which he and Telemachus decimate the suitors' numbers surely gratifies that bravado, which he's always possessed as well.

To answer this question we need to understand that one of the key desires of Odysseus as a character, which is a desire that he shares with all Homeric heroes, is the desire to gain glory through his exploits and deeds. At various points through the text, we see the way in which Odysseus rather arrogantly ignores the advice of different characters or does what he thinks is best without thinking about the consequences of his actions and what might happen to both himself, and to his men, as a result. The best example of this is when, at the start of his wanderings, Odysseus was so focussed on gaining glory that he deliberately revealed who he was to the Cyclops, and as a result brought down calamity on both himself and his men because of Poseidon's special relationship to the Cyclops.

However, by the end of the story, when he reaches Ithaca, the way in which he deliberately bides his time and disguises himself as a beggar instead of rushing into his home and declaring who he was before the group of extremely hostile suitors shows how he has developed and changed. He is not the same glory-hungry individual who often committed rash and rather vacuous actions in order to gain kudos. Instead, he tempers this aspect of his character with the need for patience, and remains incognito until he has established his position and what men are loyal to him and he is ready to strike. The text therefore indicates that Odysseus as a character very definitely learns from his mistakes and develops during the course of the epic.

Although Odysseus always wants to get home to Penelope, at the story's beginning, he is willing to dally for awhile with Circe, among others. He wants to have his cake and eat it too. By the time he gets home, however, he at least appears to be wiser and more sober. He is bent on reclaiming Penelope and delivering her from the plague of suitors who want the power that will come with marrying her. We don't know that he will be more faithful to her, but the indications are better now that he has regained home and hearth.

More importantly, Odysseus learns during his journey that displaying ego and laughing at an enemy is not smart or wise. When he puts out Polyphemus's eye, he can't resist idiotically taunting him by saying that he, Odysseus, did this. He wants to rub salt in the wound. It is important for him that the Cyclops know exactly who bested him. This is the height of putting ego gratification ahead of prudence, as Polyphemus had no idea who he was. Now, however, Polyphemus can go to Neptune, who is naturally enraged and makes life very, very difficult for the sea-faring Odysseus and his men. By the time he arrives home, though, Odysseus has learned his lesson and proceeds much more cautiously against Penelope's suitors, not feeling he has to reveal his identity in an unwise way.

From the beginning of his story (just after winning the Trojan War) to the end (coming home to Ithaca and avenging the suitors for their mistreatment of his family and household), Odysseus becomes somewhat less proud.  To be sure, he's still proud in the end, but his extended absence -- some of which is the result of his proud gloating to Polyphemus, the Cyclops son of Poseidon, god of the sea -- has humbled him a bit (especially because he was feeling so proud of himself after his victory at Troy).  By the end, he has learned to keep his mouth shut and resist the urge to boast pridefully of his victory over others, a good lesson considering how angry the suitors' families are about the loss of their family members.  He has also learned to have even greater respect for the gods, and he takes his cues from Athena in order to best assess how to reclaim his home as its rightful owner and master. 

I think Odysseus becomes slightly more humble and a little less greedy as time passes and he endures more hardship.  Early in his journey, when he and his crew arrive on the island of the Cyclopes, Odysseus's crew urges him to gather food from an inhabited cave with them and return to the ship.  However, he refuses, insisting that he wants to wait for the inhabitant of the cave to return and see if he will offer Odysseus a gift.  To put this in context, the ancient Greeks did believe in the sanctity of the guest-host relationship.  They believed that Zeus was the protector of travelers and that if a person wanted to honor him, they would treat a traveler with the utmost hospitality, and this sometimes included offering that visitor a gift.  However, the visitor was never supposed to exploit or take advantage of his host, so Odysseus is being a little greedy and presumptuous by assuming that, in addition to all this food he and his crew are eating, his host will give him something valuable.  Odysseus even refers to this tradition when he speaks to Polyphemus.  His greed, here, gets him and his men in trouble with the Cyclops, and through him, Poseidon.

However, many years later, after Odysseus's life has been endangered any number of times, the only thing he requests from the Phaeacians is their assistance in getting him back to Ithaca.  He no longer cares about getting a guest-gift; he just wants help.  This makes it seem as though his priorities are in better order than they were when he didn't anticipate having so much trouble getting home, and he seems more humble.

Growing up fatherless as he did, Telemachus could easily have been written as a bitter young man resentful of the suitors dominating his home in the absence of the patriarch; however, this is not the story of a deadbeat father running off for greener pastures.  Odysseus has been away for ten years fighting a war, and another decade trying to get home.  Prince Telemachus was a baby when his father left, but through the years has been given an informal education on the nature of his father, who is thought of as a warrior and a hero.  When Athene visits Telemachus, and he figures out that she is indeed the goddess, he realizes that his family must be considered worthy by the "higher ups", and resolves to try to become more like his father, beginning with an attempt to recapture control of his mother's household.  When Prince Telemachus meets his father at the end, we see how much the two really are alike;  Odysseus, disguised as a begger offers Telemachus his seat, which Telemachus refuses, demonstrating both men's inherent heroic and gentlemanly characteristics.  As a prince, Telemachus was entitled to the seat, but deferred to the "lesser man".  When the two men finally discover each others' identities, they embrace emotionally, then work together, father and son, man to man, to take back control of their home, thereby cementing the foundation of the family that has managed to stay loyal despite a twenty year separation.