It never hurts to dream, especially when you're in a rut at work. With jobs scarce, the temptation for the resume to stray in other directions is great. Moreover, close to half of all baby boomers are now in their 50's, many itching to fulfill a youthful ambition — before it's too late. But, unless they've done a lot of research, their experiment can backfire.

For many people, of course, switching careers can be liberating. Although the government does not track how often Americans do it, it calculates that they change jobs at least eight times on average by the time they are 55, so they do have some practice in starting over again.

And a study released in April by DBM, a human resources consulting and outplacement firm in New York, found that 72 percent of unemployed professionals changed industries (but not necessarily professions) in 2001, up from 52% in 1999, while 16% went into business for themselves.