In a recent post by Bill Baer (Microsoft SharePoint Senior Product Manager), he indicates that anyone who has installed SharePoint Server 2013 who wants to be able to install future product updates, should install the SharePoint Server 2013 March 2013 Public Update. See a full description.
He goes on to say the following:
“Q: Do I need to install the SharePoint Server 2013 March 2013 Public Update?
A: The SharePoint Server 2013 March 2013 Public Update establishes a baseline for future product updates and must be installed to support the installation of future product updates.”
When installing the update, remember to follow his outline process of stopping the SPSearchHostController, OSearch15, and SPTimerV4 services before installing the update or you will be waiting for a long time (could be up to an hour or more) for the update to complete, especially in a farm environment.