Not sure what to do? Listening to your gut can be helpful, or harmful. Here's when to know if you should be listening.

Moving from Portland, Maine, to Portland, Oregon
Act on it. Intuition is most useful in ambiguous, complex decisions, like relocating or taking a relationship to the next level, says Antoine Bechara, Ph.D, associate professor of psychology at the Univeristy of Southern California.

Selling your house
Ignore it. Intuition doesn't trump research, and real estate trends are more predictable than the stock market. So do loads of homework before you accept a bid or make an offer.

Sending a ticked off e-mail
Ignore it. When you're upset, you're likely to make irrational decisions that only feel like intuition, says Oliver Turnbull, Ph.D., a researcher at the University of Wales.

Reaching out to an old friend
Act on it. "When I get a phone number in my sleep or in a deep meditative state, I always call it the next day and am rewarded--that's intuition at work," says Judith Orloff, M.D., author of Intuitive Healing.

Taking a test
Ignore it. There's a 50-50 chance your gut will be wrong. In a recent study at the University of Illinois at Urbana-Champaign, 51 percent of students who erased their first mark on a multiple choice exam went from wrong to right.

Seeing your doctor
Act on it. There's wisdom in your body, Orloff says. Don't ignore subtle physical changes. It could be your system trying to warn you.