There are split opinions about how long a person should reside in US after they obtain green card. The majority says it is 6 months. Some say it is 1 year. As a result, some are scared to leave US even for bona fide reasons, such as for work. Especially for EB5, EB1 (L1 Visa) investors, it is a massive challenge because in order to sustain their expense in US, they have to continue to work in their own country. Thus, the answer that follows should be very helpful.
There are two levels of requirements. One is to keep the green card. The law stipulates that in order to prove that the green card holder does not intend to abandon the permanent residence, the green card holder must stay in US in continuous manner, that is to say, he cannot be overseas for longer than one year. However, if a travel document is obtained before the long absence occurs, he can be considered as having complying with the requirement.
On the other side, if a person is absent from US for longer than 6 months, the continuous residence is broken for the purpose of naturalization. Of course, there are exceptions to this rule too. To find out whether you are eligible for naturalization, you are advised to consult a lawyer. For better result, hire a lawyer for your application.