No matter what you do for a living or where you live, staying up to date and completive in your job market is important. You must know when it is time to further your education.
In comparison are you undereducated compared to others in your field? Times change, if you started in the field twenty years ago and did not have to have a master's degree then, but people coming in the profession does you may want to look at taking that extra step. If you do not you may be risk being obsolete or have trouble finding employment in your field if you ever loose you job.
Step2
Do you feel you skills are not a specific as those who are coming in new to the business you are working for. Investigate what you are lacking in, a refresher course or a course to bring you up to date may be all you need.
Step3
Do you feel lost when someone is talking about a widget. Are you wondering why they are talking about furniture. I you are unable to keep up with new technology by your self it is best to take a course or two to bring you up to date. The last thing you want to do is loose a promotion because you are not up to date on the newest technology.
Step4
Can you not go any further in your field without further education of some form. If so it is time to step it up. Don't loose a foot hold in working up into a higher paying position.
Step5
Are you doing the job of a professional but not getting paid for it. If you were hired for a job that usually requires a degree but you do not have one, do not be surprised that your paycheck may be greatly lower compared to other doing the same job. Go for the education, it will only help you in the long run. Check with your company they may have programs to help pay for continuing education.