For the ease of use of recurring regex' we have the possibility to define these in the global administration as a named entity that can be reused in the various places regex' can be used by using the name prepended with a @.
As we also (re-)use a set of time periods in various places (media, maintenance, actions, dynamic item intervals, etc.) it would be nice be able to globally define time periods as well so that we can reuse them in various places. This makes it a lot easier to update a time range in one go. Also it will prevent a lot of user errors.
Of course, it would be nice to create, edit, and use these via the API as well.