May 13, 2015 is an extremely important day for US design patent filers. Why? Because if you are smart about May 13, you can get a US design patent with a fifteen-year patent term rather than a fourteen-year patent term.
US design patents resulting from applications filed on or after May 13, 2015 will have a 15-year term. This is an improvement over the legacy term of 14 years with which we are all familiar.
A filer who has the discretion to pick when to file a US design patent application (perhaps because it claims priority from a fully enabling non-US design application filed on or after November 13, 2014) might be smart to postpone the filing of the US design application until May 13, so as to obtain the extra year of patent term.
A filer having a pending US design patent application that will be pending on May 13, who has a plan to file a CPA (continued prosecution application) or continuation or divisional patent application in the near future, might be smart to postpone the filing until May 13, again to obtain the extra year of patent term.
Finally suppose you are a filer with a pending US design patent application, and suppose that until now you had no particular reason to think of filing any further application. As of now, given how things will change on May 13, you might want to file a CPA, to get the extra year of patent term.
What makes May 13 so special? May 13 happens to be the day that is three months after the day (February 13) that the US deposited with WIPO its instrument of accession to the Hague Agreement. The Patent Law Treaties Implementation Act says that that day is the day that US design patents will start getting a fifteen-year patent term instead of the legacy fourteen-year patent term.