Using a 401(k) plan to save for retirement is an attractive option: You get tax advantages, the funds are automatically taken out of your paycheck for you and sometimes your company even matches your contribution up to a certain amount, which is essentially free money.
But many Americans don't have access to this specific retirement tool. "Roughly half of all households are offered work-based retirement plans at their current jobs," researchers at the Stanford Center on Longevity point out in a 2018 report, "Seeing Our Way to Financial Security in the Age of Longevity."
"A family is considered eligible to participate in a work-based retirement plan if either spouse/partner is included in any pension or retirement plan or any tax-deferred savings plan connected with their current job," the research team notes.
Here's the Center's breakdown of eligibility and participation in work-based retirement plans for families at different ages: