In the short term, you should tweak your resume based on each job you apply to. For example, if one position you’re applying to seems to weigh a certain responsibility or focus over another, you should be sure your resume conveys your expertise in this area. At the same time, you should be updating your resume with your experience as it develops, adding any new skills you’ve learned, courses you’ve taken or awards you won.
One of the biggest mistakes you can make when applying to jobs is sending the same generic resume out for each one. Sure, you can apply to more jobs if you don’t take the time to personalize your resume each time, but chances are you won’t get interviews from any of them. If you take the time to tailor your resume, even though you’ll be applying for fewer jobs, you’ll get more interviews.