We hold this truth to be self-evident: Confidence breeds a signature style. The hair, the shoes, the nail color send the world a consistent message about who we are. But a life of engagement and accomplishment brings inner change that we may not think to outwardly express. So for 2011 throw a reinvention revolution—and show the world what you already know.

Change, it turns out, is one more thing that’s wasted on the young. A teenager stares into the mirror for hours, desperately seeking an answer to the question, Who am I?

The possibilities—and the ever-morphing looks that ­result—can differ dramatically from day to day: I am sexy (cue the black eyeliner and bandage dress); I am punk (nose rings, anyone?). The kaleidoscopic shifting of choices about wardrobe, hair and makeup is a physical manifestation of the emotional quest for identity: Does this look match who I want to be? How about this one?

It is sweet and tortured, and, thank God, it passes.

Fast-forward to your twenties and those tentative steps toward assuming your place in the broader world. There are the first work outfits, bought in a rush of excitement and anticipation. There is the “Baby can spit up on this” wardrobe of early motherhood. These clothes, and the haircuts that go with them, are uniforms, willingly adopted and worn with a certain pride. They are a proclamation to the world—and, just as crucially, to yourself—of who you are becoming. They cement a still-nascent identity. “Any self-presentation is a performance; it is a way of communicating to others about who you are,” says Jacque Lynn Foltyn, PhD, professor of sociology at National University in La Jolla, California. I wear, therefore I am.

That was then. By now, years later, you (finally!) know who you are, down to the cellular level. You understand that you can play many roles in life and still be, well, you. Staying true to that sense of self does not mean that you forfeit the right to alter how you present yourself to the world. And yet so many of us who are proactive in other areas of our lives, from career to motherhood, are far more chary when it comes to making any noticeable change in our appearance. We can be held back by the fear of appearing vain or ridiculous, or by an ingrained puritanical reluctance to draw attention to ourselves. But those are self-imposed limitations—and haven’t you had enough of those? As the 20th-century psychologist Carl Rogers famously observed, “The curious paradox is that when I accept myself as I am, then I change.” When you truly know who you are, the act of reinvention stems not from insecurity but from confidence. It is not self-doubt but self-expression. It is not, Who am I? but This is who I am. And this. And maybe this, too.

“As adults, you’re playing with boundaries, not identities,” says Judith Sills, PhD, a Pennsylvania-based psychologist and author of Getting Naked Again. At its best, tweaking your appearance is not the incessant and increasingly desperate-seeming rebranding that Madonna goes in for. It is not about meeting others’ expectations of how “someone like you” should present herself to the world. And it is certainly not about trying to look younger. It’s about choice. Choosing to make a change in presentation, whatever it may be—going blond, going short, going executive suite—can be a way to channel different aspects of our personality, the different selves residing within.