Immigration Law Questions? Ask an Immigration Lawyer.
The B1/B2 visa permits you to enter the US for up to 1 year initially (though usually 6 months is given if you do not have a reason to stay for longer), and renewals can be in 6 months increments if warranted. You have to apply for these.Your period of authorized stay is governed by your I-94, which, if you enter the US by air, will consist of a passport stamp plus your I-94 online record,
once you arrive back into your country you can come to the US, however you need a good reason to come after just a short time, 60-90 days may be best before you try to come back.