Trimming my CV; or, what is appropriate to have in a CV at a given career stage
As has been suggested above, keep one version of your CV which is complete with everything you've ever done, and then trim it down as needed for a particular purpose.  I keep my CV up-to-date with lists of publications, conference presentations, grants, courses taught, graduate students supervised, committees served on, etc.  It's a very long document, but its easy to cut/paste what I need in various situations.