By default, Dropbox saves all deletion and version history of your files for 30 days (or longer, if you have a Dropbox Professional or Business account).
If you're a Dropbox Plus user, and you previously purchased EVH, you can recover a deleted file or revert to an older file version at any time within a year of a deletion or edit.
Previous versions and deleted files do not count against your storage quota, with or without the EVH add-on.
Removing a shared folder from your Dropbox is not the same as deleting that folder. After you remove a shared folder from your Dropbox, EVH is no longer in effect for the content in that shared folder because the shared folder is no longer linked to your account. If you add the folder again within 30 days of removing a folder from your Dropbox, deletion and version history of files from before the folder was left are recoverable with EVH.
Depending on your plan and if you purchased EVH, your version history is available for a specific length of time. We'll call this your "version history period."
If you create a file, and then edit it after your version history period elapses, only this most recent, edited version of the file can be recovered.
For example, imagine that you have a file called myfile.docx, and that you have a 30 day version history period. If you created myfile.docx on January 1st, and then edited it on March 1st, only this version from March 1st is available in your account.