I work at / for two different companies, so I have the Contractor method and the Client method here.
Contractor Method
Drawings come in and are filed on an 'Originals' drive as they are requested.
O:\Client\JobNumber\ORIG01\
O:\Client\JobNumber\ORIG02\
O:\Client\JobNumber\ORIG03\, etc...
Our current practice also includes creating and maintaining a CD as a backup plan, but it's REALLY labour intensive and for the number of times we've had to go back to the CD, it's really not worth spending the time to do it. Besides, they should have a better / more reliable backup system for their server in case something happens. This practice is soon to be tossed out the window for reasons mentioned above... and they ARE going to be getting a more reliable backup system in place.
Then they are COPIED to our Work drive
W:\Client\JobNumber\
That's where we modify the drawings while keeping the filename and drawing number the same. All clients have different revision standards, so it depends. (I'll give an example below in Client Methods).
When work is complete, they get MOVED from the work drive back to the originals drive but in a Transmittal directory.
O:\Client\JobNumber\XMIT01\
O:\Client\JobNumber\XMIT02\
O:\Client\JobNumber\XMIT03\, etc...
We then create yet another project CD to file with the hard copy of the project. I don't have a problem with this CD... it's the first one I hate!
Now, the Client Method
This particular client uses Synergis Adept which maintains revision history for each drawing or file that gets modified. File names and drawing numbers all stay the same, but when a drawing needs to be updated, the users sign the drawings out to a work area, modify them and rev them up from (ex.) Rev 5 to Rev 6A. If there are subsequent changes / it goes up to 6B, 6C, and so on until the As Built stage when the Alpha gets dropped and we just go up to Rev 6. The drawing is then signed back into the proper library but you can always access the older revisions if you want.
There are all kinds of ways to do it, but I believe you should always try to keep a copy of what you started with and what you ended up with.
Hope that helps...
We keep a copy of the original and the new file is suffixed with Rx where x is the revision number.
Before I am lambasted for doing this, let me explain why ...
Since you know it's "worth" a lambasting, I'll leave you alone.