The debate that never ends. Here's the actual answer — and it depends on fewer things than you think.
Less than 10 years of experience: one page. 10+ years of directly relevant experience: two pages maximum.
That's it. Everything else is noise.
Recruiters spend an average of 7 seconds on initial CV screening. A one-page CV forces you to prioritize ruthlessly — which is exactly what hiring managers want you to do. If you can't summarize your value in one page, the assumption is that you can't prioritize in your work either.
Even in these cases, every line on page two should earn its place. If page two is mostly older jobs from 15 years ago, cut it.
Instead of asking "one page or two?" ask: "Does every line on this CV help me get this specific job?"
If the answer is no, delete it — regardless of page count.
Reducing margins to 0.3cm and using 9pt font to squeeze everything onto one page defeats the purpose. A well-formatted two-page CV is better than an unreadable one-page CV.