We discontinued our subscription to Legal L.C. Subject Headings Weekly List but can get the information through HeinOnline. It is released quarterly. I have printed the pages from HeinOnline and insert them into the binder after I have downloaded the changed subject headings from OCLC and imported them into the Cataloging Module and changed the subject headings to the new form.
You can subscribe the the RSS feeds, Closed Dates in Authority Files from OCLC ( https://www.oclc.org/en/rss.html ) and Library of Congress Subject Heading Weekly List from the Library of Congress (http://www.loc.gov/aba/pcc/saco/cpsoed/cpsoeditorial.html ). I have one of the circulation workers search the Closed Dates list in the OPAC and they highlight the names that need to have changed authority records downloaded. I then download the updated files and make the needed changes to the bibliographic records using the "Catalogers Toolkit" available from Northwestern University ( http://files.library.northwestern.edu/public/root/ ) This is also the location to download the very helpful and necessary Spine Label Printer and Location Changer programs that work alongside Voyager.
In the past we have not used a service to get name and subject heading authority files, but I have downloaded new files as needed when new names or subject headings appear in bibliographic records
This link is to the LC page containing online subject headings
http://id.loc.gov/authorities/subjects.html
LC Authorities help is here
http://www.columbia.edu/cu/libraries/inside/units/bibcontrol/cpm/cpmcod/cpm2045.html
this is an alphabetical list of the headings
http://www2.hawaii.edu/~chopey/H1095.htm
this has more how-to explanations
The information will continue to be available as part of the Library of Congress Subject Headings and in Classification Web and Cataloger's Desktop.[none of which we get]. The Subject Headings books are available free through HeinOnline.
We have 2 books that we kept that are dated but still useful; shelved in Room 214 by the big red LC Subject Heading books :
--Free-floating subdivisons: an alphabetical index, 19th edition - - - Z 695.U48 2007 [23rd, 2011 was the last one published in paper]
--Changed subject heading subdivisions through July 2010, 2010 edition - - -no call number
Abridgments
Addresses, essays, lectures
Collected works
Examinations, questions, etc.
Of course there are many more that have been deleted or changed but we had used these in the past.