SPRINGFIELD, Va. — About 800,000 service members move each year — nearly half during the summer. Moving is a ritual repeated nearly every three years on average for military families.

It's also one that Joanna Williamson and other military spouses say could be made easier.

They are asking Congress to let military spouses opt to claim the same state of residence as their wives or husbands, who are allowed by law to keep their original residency as they relocate.

Having that option, the spouses say, would prevent many hassles associated with every move, such as obtaining a new driver's license and reregistering to vote. In some cases, it would eliminate the need for couples to file separate tax returns and lower the income taxes that some spouses pay.

"It may seem like that's just such a tiny little thing to get your driver's license changed and go change your registration. How is that such a big deal? When you move over and over and over again, it starts to become a really big deal," said Williamson, 38.

The move to Port Hueneme, Calif., about 60 miles northwest of Los Angeles, is the sixth in eight years for Williamson and her husband, Lt. Cmdr. Marcus Williamson, 39. Days after they arrive in California, he will go to Afghanistan for his third war deployment since the Sept. 11 terrorist attacks. She will enroll their two children in a new school, move the family into the new house, then head to get a new driver's license.

Congress passed the Servicemembers Civil Relief Act in the 1940s to help eliminate the hassles of moving so troops could concentrate instead on fighting. Under the law, service members who owe taxes on their main income pay it in the state of residency.

A little more than half of all troops today are married, a higher percentage than in World War II. But being married to a service member can be a professional sacrifice.

Military spouses are less likely to be employed, more likely to be seeking work, and earn less than those married to someone in the civilian workforce, according to a 2005 Rand Corp. study. Frequent moves are a major factor in the difference.

Williamson said she would like to have the same residency as her husband: Gainesville, Fla., where they met and married, where his family lives and where they plan to retire. Instead, her residency has bounced around to Mississippi, Rhode Island and Georgia over the years, while his remained the same.

"I think at this crucial time ... years into our conflict, it's one of the small ways that we can say that we recognize the sacrifice of the military spouse," Williamson said.