Sometimes, using a recruiter is the only way in to a job (companies often do this to outsource the process and have exclusivity on the process, and their first job is to weed out unqualified applicants before the interview process begins). They also, by profession, rely on a large professional network - which can be leveraged in various powerful ways as you seek out new opportunities. Recruiters often have long-term relationships with company clients and have earned trust with them - this means if you are vetted for the job, the company is more likely to consider you. Since recruiters get paid by clients, and you are the best candidate, your payday is their payday too. A shared goal will help drive their advocacy for your placement in that perfect job. In turn, they will also passionately work with you to get you ready for that job interview and work alongside you to make sure things go well for all parties.