This is a question I field all the time. My answer is fairly simple—you should hire a career coach when and if you feel stagnated and unable to move forward to reach your career goals. Think of it as a clogged pipe. You could try Drano. You could try snaking the drain yourself. Either or both might work, but when they fail repeatedly, you call the plumber. Calling in an expert to assist in an area in which you do not have expertise is not a personal failing. Rather, it is a smart investment of your time and money.

Having said that, you need to be smart about who you hire. Some coaches are great at helping you. Others offer little more than advanced Googling. How do you decide with whom you should work? Think about the following:

What do I really need help with? Are you trying to change industries? Are you looking to advance to the C-suite? Maybe you get lots of interviews, but no offers. Could working with a coach who specializes in interviewing techniques help? Think of selecting a coach the way you would go about selecting a doctor. You wouldn’t go to a cardiologist for a rash. You would go to a dermatologist. Seek out the appropriate specialist for your unique situation.

Do they have an online presence? Any coach who is not active on social media and his own website is pretty much irrelevant. Personal branding is a huge component of career management, so look for a coach who has developed a strong brand. Someone with a strong brand will understand how critical that is in terms of advancing your career.

Are they active in the job seeker community? Do they write? Do they facilitate workshops? Do they seem to genuinely care about helping people? A good coach is a thought leader and engages in these activities to share his expertise, not merely as a tool for business development.

How much do I want to invest? Working with a coach is an investment of both time and money. Good coaches are not cheap, and good coaches require you to do a lot of work. Are you able and willing to commit? Will you make the effort and muster the enthusiasm?

Once you’ve identified a few coaches who fit your criteria, interview them each. Understand each coach’s strategy and approach, and how that aligns with your goals. Remember, the ultimate goal is to get you to do something differently so that you can achieve a different outcome, so prepare to get a little uncomfortable. In the end, working with a career coach can be one of the best investments you make, as long as you both are clear on what your expectations are.