By default, the settings in Revit will prompt you to save locally every 30 minutes, and prompt you to save to central (if your project is workshared) every 60 minutes. You can easily change these settings in the 'Options' dialogue box, but this isn't recommended. Sure the popup's are annoying, and only show up when you are about to do something else, which the command is then cancelled after the save operation so you must redo it, but what is more inconvenient: re-doing a command or losing more than a half hours worth of work? I always tell people to do the save command and live with the 5 second delay, because it's quicker than re-doing everything you did.
There are two options available for saving to central. One for 'Synchronize Now', and one for 'Synchronize and Modify Settings'.
The later gives you one more dialogue box that you must navigate through, but it is a good way to keep a record of what has been happening and going on.
Even something as simple as a sentence or a couple keywords that mean something to the project can be useful later on if you are trying to determine what people did, or as I like to think about it, if something gets corrupt in the model and you must restore back from a previous version, comments can help you determine when would be an appropriate time to restore back to, or can be useful in determining when the work in question was completed.
If you use bluestreak from Autodesk Labs, the comment is also recorded with the action in the log and will appear on other people's desktop as well as the log for the files. The comments show up in italics at the end of the action.
