U.S. citizens have the right to stay abroad for as long as they wish, and they can return at any time, according to New York Daily News. American citizens can remain abroad for the rest of their lives as long as they have permanent residency in the United States.
New York Daily News further notes that Customs and Border Protection officers are also required to admit Americans who travel to restricted countries, such as Cuba and North Korea. However, naturalized U.S. citizens are not required to have permanent residency in the country. There was a time when Congress required naturalized citizens to retain residency, but these laws were repealed.
U.S. News notes that residency and citizenship are separate, and the only way one can lose citizenship is to renounce it. UPI notes that American citizens living abroad are still required to file taxes because the U.S. tax system is based on citizenship and not residency, which is a reason why many Americans living abroad for the long-term choose to relinquish their citizenship. Forbes mentions that many citizens must pay an exit tax, which is based on a person's assets, when giving up citizenship. U.S. News further explains that Americans are still required to hold a valid passport regardless of location when retiring or living abroad permanently.