It depends on what you do, who your target audience is, how competitive it is to flag someone's attention from a pool of candidates, and how competitive it is t

It depends on what you do, who your target audience is, how competitive it is to flag someone's attention from a pool of candidates, and how competitive it is to get the position. The tech field comments here perhaps capture one extreme of that with recruiters and keywords so I'll give a contrast. If you are in academia you probably teach courses, get grants, are a PI, publish and present at conferences, get awards, be invited to give lectures, contribute to books or some combination of all these over your career and your CV should reflect that. I've seen academic resumes with 40+ pages of publications, 5+ pages of grants alone without any effort at padding. This stuff is important when applying for promotion and grants, getting involved at a higher level in or out of your institution even if you aren't looking for a new job. Another case is when applying for something competitive e.g. graduate or medical school where transcripts attest to academic achievement and a CV should be highlighting various domains of their work ethic, scientific achievement, extracurricular achievements to round an individual out and score points on standardized rubrics. A longer resume e.g. 4/5 pages probably doesn't penalize compared to losing points by not reporting on this at all even if a bit excessive. I keep my academic resume around ~2 pages of core content and then a longer running bibliography. I trim sections of my life as they becomes successively irrelevant e.g. undergraduate awards/jobs/volunteering, medical school involvement/leadership/research (publications stay elsewhere), etc. as these all helped me to get a next stage but are no longer relevant.