It's very similar to Canada. Once an application has been allowed, if it was based on intent to use there's a requirement to file a statement of use, and not only a statement of use but specimens. Also, as Mr. Eisen mentioned, between the fifth and sixth anniversaries of registration in the U.S., it's required to file an in-use declaration and specimens again. As well, with every renewal, it's required to file a statement of use or an in-use declaration and specimens.
On May 12th, 2014. See this statement in context.