Question. How long can I remain outside the U.S. without jeopardizing my permanent residency status?
In order for one to be considered as properly maintaining lawful permanent resident (LPR) status, a green card holder must be maintaining a permanent residence in the United States. If one is outside the U.S. for a period greater than either six months or 180 days, the immigration inspector may start questioning whether the permanent residence has been abandoned. As a separate matter, being outside the U.S. for such periods of time can also be a problem when applying for U.S. citizenship.
 
If such an individual just makes an annual or biannual visit/s to the U.S., it may appear over time that s/he is spending more time abroad than in the U.S., and actually is living and working abroad. Then the individual is at risk of losing LPR status. If one plans on an extended stay outside the United States, it is possible to apply for a reentry permit before leaving the U.S., which is valid for a maximum period of two years. Although such a permit would not guarantee reentry to the United States, it would greatly facilitate it.