How many years should the CV go in detail into the past?
As we get older I suppose that things of 30+ years ago are not that relevant. Could I just not enter into the details of them? the CV would still cover the time from college admission up to today, but only the last 10 years would be with further explanation.
I'd say that the focus is on enough detail to address the given job requirements.
In general - you want the last 2-3 jobs, going back up to 10 years in some level of detail. But mileage varies depending on the positions you've held and the position you're applying to.
For example:
if the target position focuses on a legacy technology and you did something awesome with it 15 years ago - highlight that position.
if the target position is focusing on a wide and deep breadth of capabilities, make sure you show your breadth.
if there are areas in the near term that are irrelevant, but job history longer ago that is a direct match, de-emphasize the less relevant areas and focus the reader on the relevant experience.
For older or less relevant positions, length, company and position are fine. Figure that the reader is time-pressed and wants a fast easy to read summary of your career.
I tend to leave older stuff on there to show the complete history, but show it in less and less detail as time goes on. Mine now goes back 17 years, but they are down to 1 liners pretty much just with a company name and the dates at the start of that period.
2023 update - mine now goes back 27 years 😀
yyyy-yyyy, as long as each of them is at least 2 years, but that's marginal probably.