One of my favorite writing books, Fiction is Folks by Robert Newton Peck, has a chapter about using objects to help build characters. What a person owns says a lot about them, and can also remind the reader of important past events without the author having to do a recap.
A huge moment in Indiana Jones and the Kingdom of the Crystal Skull is when Indiana's famous hat rolls out in the dirt. You know Indian has arrived and some serious adventure is about to start -after all, if his hat's on the scene he's got to be nearby. Sometimes a certain word or phrase can take on the same importance as an object. For example, "All for one and one for all" instantly makes a person think of The Three Musketeers.
The power, I think, of catchphrases, is that they remind you how well you know these characters. You feel a little shiver of familiarity and you grin in expectation, or maybe you start to seriously worry, depending on what usually follows that phrase. Perhaps a character says "nothing can go wrong now," and you want to reach right into the story and slam your hand over their mouth because you know that something really bad is about to happen.
Catchphrases can be like movie music. The battle-cry that makes you catch your breath the same way a sudden musical swell does. The jinx words that make you shift uneasily -just as if creepy music had begun to play across the page.
Of course, a person doesn't want to overdo it with the catchwords and catchphrases or your characters become flat, but the power of catchphrases shouldn't be ignored, either. In Through the Looking Glass Humpty-Dumpty suggests that the speaker (or writer) controls the meaning of the words he uses. Catchphrases are one more trick for taming those words.