This question comes up constantly from candidates with long, accomplished careers: how far back should a resume actually go. The honest answer is that there is no fixed number of years that applies to everyone, but there is a clear way to think about the decision that works in almost every situation.
Why this matters more than people think
Older roles take up space that could be used to make your most relevant, recent experience stand out. A resume that gives equal weight to a job from fifteen years ago and a job from last year often ends up diluting the more important, more current story instead of strengthening it.
There is also a quieter risk. Listing extensive history far back can sometimes invite unconscious age related assumptions during hiring, something candidates cannot control directly but can avoid drawing unnecessary attention to.
A real example of trimming history effectively
A candidate I worked with had over twenty years of experience and a resume that listed every role since his first job out of university. The earliest entries were in a completely different field from where his career had ended up, and they took up nearly a third of the page.
We kept his most recent ten to twelve years in full detail, since that was the experience most relevant to the roles he was now targeting. The earlier roles were condensed into a single short section near the bottom, listing titles and companies only, without detailed bullet points.
The resume went from two and a half dense pages to a clean two pages, with far more visual emphasis on his recent, relevant accomplishments. He began receiving interview requests at a noticeably higher rate within the same month.
A simple way to decide what to keep
If a role is more than ten to fifteen years old and unrelated to your current target roles, it almost always works better as a condensed line rather than a fully detailed entry. If an older role is directly relevant, perhaps it was where you built a core skill central to your current path, it can sometimes earn a slightly longer mention even if it falls outside that general window.
The guiding question is not "how long ago was this," it is "does keeping this in detail help someone understand why I am right for this specific role today." If the answer is no, trimming it is rarely a loss.
What this is not about
Trimming older experience is not about hiding your age or pretending you have less experience than you do. It is about directing attention toward the experience that is actually doing the work of getting you hired, rather than spreading that attention thin across decades of history that may no longer be relevant to where you are headed next.
If you are unsure where that line sits for your own resume, this is exactly the kind of judgment call a resume rewrite is built to make, balancing your full history against what actually serves your current goals.
This is the work I do. I help people decide what their resume should be telling a story about right now, not everything it could possibly include.