Is there a limit to the number of times I may travel to the United States visa free in any given period of time?

There is no limit to the number of times you may travel visa free under the Visa Waiver Program in any given period. There is also no minimum period of time you are required to remain outside the U.S. before reapplying for admission. However, if you are a frequent traveler to the United States you should be sure to carry with you, for presentation to U.S. Immigration, evidence of your residence abroad to which you intend to return at the end of your visit, together with evidence of funds sufficient for your support while in the United States. If the immigration inspector is not convinced that you are a bona fide visitor for business or tourism, you may be denied entry to the U.S.