Re-entry on Visitor's Visa

[greco]

My mother-in-law is with us till Oct 07 [Since Jul 07, 3 months]. Is there a law/guidance that prescribes the time she needs to be out of US before she can visit us again ?
She is planning to visit us again in Feb 08.

[immihelp]

There is no such law but read the last paragraph at https://www.immihelp.com/visa-stamp-...ration-in-usa/