I am a bit late to the party, but …
I have my CV down to four pages. I personally try to imagine I were the interviewer and ask myself how many years of experience I would consider relevant and have decided about 10 years should do it. That said, I currently have 12, as there is one job that I don’t want to “drop off the end”. I finish my CV with “details of previous positions available on request”.
But, what I haven’t seen addressed here is whether the skills are consistent or if there is some change. I have *cough* decades developing embedded software for the telcomms industry, which segued into satellite communications. There’s not much point in detailing all of those telcomms projects, although I do make the reader aware of the total length of time spent on them.
In the last ten years, I have spent a year in automotive, in avionics and in a satellite itself, rather than the ground side as normal. It’s all embed, so all relevant, but the question is what a potential interviewer will think of my avionics experience – to choose one at random – as the years go by. “hmmm, it’s been X years since he did any avionics. I wonder if he still groks the different Design Acceptance Levels. Never mind, we can soon bring him back up to speed on that. DO-178 is more important, though. And if has forgotten his ARINC protocols, we mat as well recruit someone with no avionics experience”.
So, with a mixed career, the question is which experience do you want not to “fall off the end” if you restrict your CV to 2 pages, and how much will an interviewer believe you still remember.
Whereas, with a long career in a single company, position or industry niche, you can probably use 2 pages plus “and X years similar experience – details upon request”.