When can one come again to US on B2 visa(Multiple entry visitor VISA)? -

My mother has multiple entry visitor visa. She stayed in US for 6 months. She is going back to India. And when can she come back to US again? Is there is any rule of staying in US not more than 6 months in in year kind of . Please give me insight and any legal linksthanks.

There is no written rule; it is dependent upon the Immigration Officer; be aware of the fact that a B-2 visa is issued for the purpose of visiting the United States and not for the purpose of residing in the U.S.; someone who tries to apply for re-entry after a short period my be considered to try to be a de facto resident and may be denied entry. After staying for 6 months she should at least stay out for another six months before she re-applies for admission.https://help.cbp.gov/cgi-bin/customs.cfg�� ..