I typically keep versioning my documents after every major design change or after every client review.
Helps me tie meeting notes and events to document versions.
I do the versioning manually, as clients are not always comfortable dealing with automatic version control systems (and honestly, I don’t have much experience with them either)
It might lead to greater storage space usage, but well worth being able to jump back to a previous version without waiting to restore it and such.
Current version of a document stays in the working folder, and previous versions are placed in a sub folder called “_old”.
Oh, and export folder is completely different, and export folders are labeled by date and version number both.