Immigrants who are in the country on family or work-related visas often choose to become lawful permanent residents by obtaining a green card, which affords them more rights.
In order to become a lawful permanent resident, a person must be physically present in the United States. A spouse, minor child or parent of a U.S. citizen is able to apply for a green card if he or she entered the United States with a valid family visa and the entry was with inspection, admission or parole.
A fiancé can apply for a green card after marrying his or her U.S.-citizen fiancé within 90 days of moving to the United States. Fiancés or spouses of U.S. citizens are often K-1 or K-3 visa holders when they apply for a green card. Those who have been married for less than two years will be given a "conditional green card." In 21 to 24 months, it's possible to petition to have the conditions removed.
Removing the conditions from a green card is usually easy of the applicant is still married at the time of the petition. Even if the marriage has ended, it is still possible to have the conditions removed, but it is more difficult.
People with business-related visas must apply for their green cards before their visas expire. On the other hand, spouses of U.S. citizens are able to apply for a green card even after their visas have expired.
Once granted lawful permanent residency, the green card holder is not required to spend any certain amount of time in the United States. However, the United States must remain the green card holder's primary home. Additionally, the green card holder cannot spend a continuous year or more outside of the United States without first getting a reentry permit from U.S. Citizenship and Immigration Services.
For more information on lawful permanent residency, talk to an experienced immigration attorney in your area.
Source: NY Daily News, "Green card residency requirements," Alan Wernick, Oct. 3, 2012