I'd also suggest using the Save As... command to create a new version with a different file name in your word processor. Doing this, if you accidentally save over your work (classic example - I once hit Select All (ctrl-a), hit the space bar, and saved over my file, making it blank. All in a fit of spastic hand motion. By having an earlier version under a different file name, I recovered almost everything).
Also, the "Save" command only saves changes to the document, making it larger because of all the save-tracking metadata that's saved with the file. Using Save as... forces the file to be rebuilt without that extra data, making it smaller and potentially removing corrupted data that could cause problems later.
Try it - save a document normally, then use Save As to create a new file. The new file will be quite a bit smaller.