valid use date(USP Reference Standards (RS) do not carry expiration dates in the traditional sense. Instead, they are assigned Valid Use Dates. As long as a lot is listed as being the "current lot" it is valid and suitable for use. Once a current lot is depleted, it becomes the "previous lot." At this time a valid use date is assigned, which is typically 3-12 months from the date of depletion. usp.orgamatsyuk)
date of first use(What is the difference between the "date of first use anywhere" and the "date of first use in commerce"? The date of first use anywhere is the date on which the goods were first sold or transported or the services were first provided under the mark even if that use was only local. The date of first use in commerce is the date on which the goods were first sold or transported or the services were first provided under the mark between more than one state or U.S. territory, or in commerce between the U.S. and another country. The date of first use anywhere must be the same as or earlier than the date of first use in commerce. uspto.govAlexander Demidov)
