Question about 6 months US stay

[bhairavi]

Apologies in advance if this question has been asked already, but I wanted to know about the 6 months tourist visa stay.

My parents have 10 year multiple entry US visa. They are planning to stay here for 6 months and we already booked the return ticket back to India. But I want to know if the time resets if they go to some other Country and come back to the States. For example, if they want to extend their stay longer, can they go to Canada for 10 days and when they come back will the time reset to 6 months? Or is the rule that they can only stay for a maximum of 6 months in a year?

Any help would be appreciated.

Thanks in advance.

[daggit]

Are they planning to live for many months in the US?

[b1/b2 master]

They can leave and come back. but it won't work forever.

The best plan is to ask the CBP officer upon arrival to stamp them into the USA for more than six months form the start.