As an ex-hiring manager, resumes over 3 pages were almost guaranteed to have a ton of useless (to the reader) detail that obscured the signal and any kind of messaging the candidate wanted to convey with this document. This is such a critical thing that many people miss - the product you are selling is your experience, and the resume is the sleek marketing document, not the dry technical specification (I don't mean this literally, but 5-15 page resumes, I'm looking at you).
Mine is one and a half. I think it's more important that it's easy to read, if you're trying to fit everything into one page and it becomes dense or overly brief it defeats the purpose of the rule.
These rules are made up employment coaches (or whatever they're called) who need content to write about and want you to hire them for their consulting services.
A Resume is a crapshoot anyway, anyone can put anything they want in it - most of it is unverifiable until tested. As long as you have the required skillset, the important thing is that you don't act weird in the interview.
However, I would excise older jobs if they are not relevant, or didn't make you look better. "Mail room intern (trial basis)" or "Junior fry cook, McDonalds (6 months)" are not going to help you get a senior dev role, so just leave them off and save the reviewer's time. Your resume doesn't have to be a complete, unbroken history of your employment to be useful in my opinion.
I’ve never had a one-page resume. It was two pages until recently. I’ve played a lot of roles (backend, front end, kernel, system level, infrastructure, product design, leadership, consulting) and a longer resume makes it easier to show that versatility — its my major selling point.
I think what to put there and how to phrase it is MUCH more important than length.
To more directly answer your question. Your resume can go to two pages if, after you’ve VIGOROUSLY edited your resume down for clarity and concision, it ends up over one. People will hold up some number of years of experience or another metric, but really you can have two if and when you can seriously justify every word on the page that takes it past one.
If you have more than 1 page the first page should summarize it in a way that gets the attention of whoever is reading it.
I never penalize or reject candidates based on having a multi-page résumé, but I tend to see a strong correlation between candidates with great one-page résumés and great written communication skills. It shows that they've spent the time to consider what's relevant to the hiring manager/recruiter/etc.
IMO, keep the résumé short and sweet, and stick to the highlights, with a heavier emphasis on more recent experience. If you really want to dive into more detail on something, write a cover letter tailored to the position/company you're applying for.
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.
Don't get hung up on the length - resumes are 100% digital nowadays
Do get "hung up" on precision, action, and measurable achievements (whenever possible) in your resume's bullet points
Do be careful about spelling, listing relevant "non-work" experience, where you went to school, etc
Do be as brief as possible - but no briefer
In interviews, I've had people read that far down and it's worked, they got exactly what I wanted them to out of it. In other interviews, it's clear that they didn't care, but the resume still got me in the door. They still got the most important parts up top.
And of course, it depends on who you're interviewing with and what you're applying for. The rules aren't so hard and fast, esp. when you're sending over digital copies.
If you are using your space smartly and it takes two pages to tell that whole story, OK. If you can reasonably trim it to one page, you should.
For the North America, a cover letter and 1 page are standard. I've had a 2 pager, but I'm also old AF and changed jobs regularly. I don't use my entire history, but stick to the relevant stuff. If it's something that helps them have a better understanding of who you are, then go for it.
My 2 cents.
I have more detail in the newer jobs. It's 3 or 4 now, it goes back to 1999 there isn't much space with alternating between perm and contract.
Worked at places between 3 weeks and 3 years, but probably about 20 or so listed and other info.
It probably depends on the industry. I think academics and jobs where publications are important tend to have more pages.
Had to trim some details of old roles and make font a bit smaller.
During interviews I have the chance to expand on my experience.
Nobody interested what I can manage Kerio WinRoute Firewall 6 and I don't want to work where it could be a factor in my employment.
I think it's fine either way.