2 answers
Katy’s Answer
This can be a difficult situation to read depending on your career field. Generally, I'd say you can judge based on the degree that a person in a job you'd want has, but that isn't always the case anymore. I would say, base that decision more on your feedback from employers and potential employers and your own personal goals. Do you want to be referred to as "Dr." or do you just want a good job? The final decision you make should be based on your personal desires, not necessarily on your career, but you can make a good educated guess on the necessity of additional degrees based on what the requirements are to the jobs you want most. Do they all say "bachelor's required, master's preferred"? If so, you might want to consider that advanced degree. However, at the risk of spending an additional $20,000+ on another fancy piece of paper, you can always make up for that degree with experience. It might take a few years of low or unpaid internships and entry-level positions, but you can often do better with additional employers on your resume instead of additional letters after your name.
Mike’s Answer
I found it helpful to look at job postings and descriptions of careers that I was interested in, and then look at what the education requirements are for that role (e.g., requires a Master's in Public Policy, Education, etc.). This can give you a good sense of what kinds of jobs are available to the type of study you're interested in.
Additionally, I found it helpful to talk to a couple of people who were in these careers already and hear about their advice on education (e.g., was their degree useful, what would they have done differently, etc.). Once you have a couple of degree plans, have a look at a couple of degree programs and see if any look like a good fit based on your interests, budget, location, etc.