It tells them you are prepared and competent. Employees with Master's degrees usually command higher salaries and sometimes have access to jobs that ordinary college grads do not. But the sacrifices still may not be worth the effort. Advanced education has to be weighed against the real world experience you might gain during the same amount of time. While a Master's degree is a luxury in most fields, in the legal and medical professions it's required.
Specialized industries demand specific education.
The same goes for the admissions process to those schools. Lawyer wannabes will need to ace the LSAT, while those looking to play doctor must tackle the MCAT before going anywhere. Law students can expect to give up three years of their time, if attending school full time. For more information, hopeful medical students should check out the Association of American Medical Colleges at aamc.org. For the budding attorneys out there, check out the Law School Admission Council at lsat.org.