You must spend at least half of the time of the 5 or 3 year period inside the U.S., and you cannot have any absences greater than 180 consecutive days. If you travel outside the U.S. for a day and return the same day, this period will not count as time spend outside the U.S. If you spend a lot of time outside the U.S., you may need to prove your physical presence with documentation demonstrating that the U.S. is your residence. Please consult with an attorney for further advice.