how often should you update your resume

when a recruiter calls or when there is an opening in your dream company , that is not the time to update your resume

you should update your resume , ideally ,

after an appraisal or

after you have done some major achievements in your career

add important accomplishments and job updates ( eg promotions , cost savings , project upgrades , etc)

update your references at the end of the resume with their contact information

talk to your manager with what skills will be needed in the future and train for it or ask for training so that you will be relevant in the future as well to your employer