5.8 Work with Versions of Documents

     Applications that support OS X’s Version feature automatically save documents as you change them. Each time an application saves a document, it creates a version. Applications create versions at least every hour, and more frequently when you are making “significant” changes to the document. You can also save a version at any time. Versions are useful because they enable you to go back to a previous edition of a document. OS X saves hourly versions for 24 hours. Daily revisions are available for a month, after which time weekly versions are available.