Bill Brown and his wife have started off retirement comfortably and have come to enjoy some time together (and apart) after years of juggling busy careers.

In Brown's opinion and experience, he told Business Insider, "the No. 1 rule for an early retirement, a retirement that's simple, is this: Be married."

"My wife and I've been married 41 years," added Brown, who retired at 65 and lives near Columbia, South Carolina. While he acknowledged that at first it was a shock to have so much time together after years of being apart, he said marriage "makes retirement a lot simpler" when it comes to money.

"We don't have to both go out and find a single-wide trailer that we could afford individually," he said. "Instead, we have a nice $200,000 home that we live in together."

And there's also the fact that two retirement incomes can be very helpful for providing extra cash. "You have two retirements to support one family unit," Brown said. "If it were just me, I could do it, but it would be a whole different lifestyle," he added. He regularly travels for fun with his wife, as well as for conferences for some consulting work.

"It isn't easy being married 41 years," Brown said. "My wife will tell you that."

Brown's experience finding retirement more affordable with a spouse isn't unique. Even for families who aren't earning two incomes, a nonworking spouse can collect Social Security income based on their working spouse's earnings to be used as a supplemental income in retirement too.

"A higher-income family could have some planning opportunities whereby they could collect half of the spouse's benefit and let their own grow," David Frisch, a financial planner and CPA at Frisch Financial Group in Melville, New York, told Business Insider.

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Frisch is describing the fact that delaying claiming your Social Security benefit means you'll get a higher monthly payout. While Americans who have worked for at least 10 years can start claiming benefits at 62, they wouldn't get 100% of their benefit unless they waited until age 66. In 2019, the maximum benefit for a person claiming Social Security at their full retirement age is $2,861 a month.

"One spouse who's 68 or 69 can wait until age 70 to collect, but another spouse who may be 67 can take, let's say, half of the other one's benefit," Frisch said.

This strategy of delaying Social Security payments tends to be more feasible for higher-income families who aren't in immediate need of cash. "A lower-income family can't wait to delay the Social Security," Frisch said. "They have to get the income just to live and buy food and survive."

A spouse can still be entitled to spousal benefits, even if they're divorced or widowed. And, if one spouse had a significantly lower income than the other, the benefit for the lower-earning spouse could be a full 50% of the higher-earning person's, increasing the benefits a couple could see in retirement. Even if both spouses aren't working and saving for retirement, the Social Security laws can add to a couple's dual income in ways a single person wouldn't have access to.

"You don't have to be married forever," Brown said. "You can be married five or 10 years before you retire." For him, "it's about having two incomes. It makes it a lot simpler."