After acquiring your green card and the permanent residency and right to work in the United States that comes with it, you'll have a very valuable commodity on your hands that probably took a mix of luck and patience in order to achieve. As such, you'll want to follow all the rules that apply to your green card closely so you don't risk losing it.
With this in mind, you might also want to go to your country of origin to visit family and friends, the question is, are you allowed to leave the United States as frequently as you want and return with your green card still valid?
As long as you don't leave the United States and stay out for over a year, as a green card holder, you can come and go multiple times during the year. If you plan to be away from the United States for longer than a year, you need to apply for your re-entry permit via the U.S. Citizenship and Immigration Service (USCIS) before you leave for this extended period.
Usually, a re-entry permit will grant you the right to re-enter the United States under your green card for a period of two years. If, on the other hand, you break this rule and stay outside the United States for longer than your permit allows, you could be denied the right to re-enter.
The rules that apply to green card holders can change from year to year. As such, it's vital that you stay abreast of the current laws that apply to your situation and traveling out of the country so you don't risk losing your visa.