we got our E pictures back! YAY

so we are getting ready to put together save the dates. we have people invited from mulitple states and countries so they were def going to get a STD but do we need to send everyone invited a STD?
side notes: there is a huge conference in downtown (where the wedding is) that weekend so rooms are going fast...STD's would include that info...IT guests wouldn't need that but OOT guests would so STD's are necessary
we are inviting work people...I don't really think they need STD's?
any help would be great! Thanks!