Career changers can't expect much here. Many large firms are contacted by 50 to 200 job seekers each day. This means there will be instances where a recruiter calls you months after the firm first receives your resume. You will be most popular with recruiters if you are a person who will explore attractive situations but who is not too unhappy with his current employer. The chance of a recruiter filling a job that is right for you at the moment you contact them is small.
Recruiters prefer people who have credentials on paper that are easily marketable to their clients.
Initiate recruiter contacts at an early stage. Send your materials to as many recruiters as possible since response rates are low. Never be negative with recruiters about your current or former employer.