Here is a link right from the source. Generally you should be in the US more than abroad (ie in US >6 months in a year.) If you plan to be out more than an year

Here is a link right from the source. Generally you should be in the US more than abroad (ie in US >6 months in a year.) If you plan to be out more than an year, you should get a re-entry permit. https://help.cbp.gov/app/answers/detail/a_id/820/~/can-a-u.s.-lawful-permanent-resident-leave-multiple-times-and-return https://help.cbp.gov/app/answers/detail/a_id/820/~/can-a-u.s...