One reason married couples accumulate wealth more easily than their single counterparts is that they have lower overhead. It costs less to maintain one household than two.
Similarly, couples can take advantage of economies of scale that make buying for two more cost-effective than buying for one.
For instance, grocery shopping for one can be just as expensive as buying for two.
"Larger quantities are usually priced lower per unit than smaller quantities. This also usually applies to health and auto insurance. It is easier and cheaper to add another person to a policy than to take out a separate policy," says Michael Greaney, CPA, of Equity Expansion International in Washington, D.C.
Cost efficiencies are less obvious than the savings reaped by buying extra-large cans of ravioli or fruit in bulk.
"For a single person, finding the time to prepare dinner, do the laundry, iron clothes, vacuum, wash dishes is difficult. Add just one other person and the same or lesser effort tends to have more than twice the result," says Greaney.
A single person may be tempted to outsource some chores, and pay for it.