Physical challenges may limit your ambitions as well. "You don't have the manual dexterity, that very quick muscle learning, you have when you're a kid," says Alice Kissling, 55, assistant general counsel for American Family Mutual Insurance in Madison, Wis., who started playing the harp a decade ago.

Fitting lessons and practice into busy work and travel schedules confounds many adults. "Your focus is so fragmented," laments Washington economist and consultant Fred Flick, 55. Nevertheless, Flick, who took up the piano when he received lessons as a Christmas present from his wife 14 years ago, admits that pushing himself to play better is something of an "obsession."

On other fronts, adult learners have a leg up on Junior. They may have a sophisticated understanding of music gleaned from years of listening and concert-going, and many understand their own learning styles, says Chelcy Bowles, Kissling's teacher and director of continuing education at the University of Wisconsin at Madison. Those who can already read music and understand phrasing will find it easy to transfer knowledge from one instrument to another.

Adults are also generally more self-directed. "They come into the class knowing what they want to accomplish, and there's a lot more collaborative goal-setting," says Bowles. And for adults, the musical journey is at least as important as the final destination. That's certainly the case for Scott Anderson, 31, who hated practicing the saxophone as a kid but now is determined to play the guitar well enough to serenade the baby he and his wife expect to adopt soon. One evening a week, Anderson, director of public relations at Foote, Cone & Belding Southern California in Irvine, meets with his teacher for an hour-long lesson in an office conference room to avoid the rush-hour traffic. At lunchtime most days, he practices in a nearby park.

If you haven't settled on what instrument to play, think about your musical preferences, suggests Jill Sullivan, an assistant professor at Arizona State University's School of Music, who trains teachers in matching students with instruments. Do you like higher sounds, more mellow timbres, or brighter ones? Can you stand the blare of a trumpet, and, more to the point, can your neighbors? Then, consider your physical limitations. For instance, the trombone might be better than the guitar for arthritis sufferers.

Group classes can be a great low-cost introduction to a new instrument, as well as a chance to socialize. Check with your local community college, music school, or adult-education program. To keep your costs down, rent an instrument from a music store until you're sure you like it. Or check neighborhood bulletin boards and want ads for a used instrument.

For more personal attention, you can get a private teacher, but expect to pay $30 and up an hour. To find his guitar teacher, Anderson scouted out clubs for musicians whose style he admired. Then, he interviewed the teachers with the same rigor he applies to screening job candidates. Ask teachers how much experience they have with adults and check their references. Talk about their expectations and yours.

To get the most out of your lessons, carve out regular practice time. Hampton heads for the piano the minute she gets home. But remember, it's supposed to be fun. Even if you practice, practice, practice, Carnegie Hall probably isn't in your future--and that's beside the point anyway. Kissling says she can spend a week at her corporate law job without feeling she has made the world any better. But "when I'm making music with my friends, we know we've made something lovely." That's reason enough to keep on playing.