With all the warnings about how ill-prepared tens of millions of Americans are for retirement, it’s troubling that more people don’t talk about the advantages of homeownership as a contributor to retirement security … or talk about the calamities awaiting those seniors who rent.

The biggest next egg for most people over 65 is their home. It’s bigger than the assets in their 401(k)s, their IRAs or government pension programs. People have cut living expenses decisively by paying off their mortgages.

Yet home equity is an underrated store of wealth that can be tapped for the high out-of-pocket expenses that often accompany assisted living and nursing home care. It’s also wealth to leave to children and grandchildren.

Even so, retirement security is about more than maximizing money. It’s also about limiting expenses … and that is where houses can be lifesavers for a comfortable standard of living.

Last year, the average renter in metro Boston paid about $2,100 while monthly housing expenses for seniors who have paid off their mortgages are about $800 (mostly for real estate taxes, insurance, upkeep and utilities). That’s a $1,300 difference for a retiree.

If the renter moved instead to Phoenix, where rents are only half those of Boston’s, the average homeowners with no mortgages still spend only $400 to keep the roofs over their heads. The difference could eat up all of a Social Security check in Boston, more than half in Phoenix.

According to Zillow, the homeowner housing costs don’t even factor in the savings from homestead exemptions, which can cut 10 percent to 20 percent off real estate taxes. Renters pay those taxes in full, if indirectly.

But homes are about more than dollars and cents, another factor retirement specialists rarely talk about. They are also about neighbors and friends. Most apartment dwellers rarely know anyone on their floors and usually just a handful of people in their buildings.

The Wall Street Journal said Tuesday there may never have been a better time to own a home. Millennials can make no greater contribution to their future.