When Nancy and Robert Houchens retired, they downsized, selling their house and most of their belongings.

"We had a 3,000-square-foot home full of furniture ... and everything we own now would fit in the back of a pickup truck," Robert, 64, told USA TODAY.

But the Virginia couple has another preferred means of transportation: cruise ships. They spend as much time as they can at sea, and sailed for about nine months during the first year of their retirement. Nancy, 71, also reached a milestone in early July, sailing 1,000 days with Carnival Cruise Line since the 1980s. Robert hit the 1,000-day mark later in the month.