Whats the period for a immigrant to stay in the USA in order to travel without restrictions?

Question

Asking in part for a family member

Answer 1

Till they get unconditional Green card for ten years. Before, if they are outside the US for more than a year without obtaining a reentry permit or returning resident visa, they will lose their status.
"A Permanent Resident of the United States can travel freely outside of the US. A passport from the country of citizenship is normally all that is needed. To reenter the US a Permanent Resident normally needs to present the green card (Permanent Resident Card, Form I-551) for readmission. A reentry permit is needed for reentry for trips greater than one year but less than two years in duration.
You may be found to have abandoned your permanent resident status if you:
Move to another country intending to live there permanently.
Remain outside of the US for more than one year without obtaining a reentry permit or returning resident visa. However in determining whether your status has been abandoned any length of absence from the US may be considered, even if it is less than one year.
Remain outside of the US for more than two years after issuance of a reentry permit without obtaining a returning resident visa. However in determining whether your status has been abandoned any length of absence from the US may be considered, even if it is less than one year. "

Answer 2

It depends on immigration status of the person. You need to clarify that.