In response to your first question. No Autodesk Revit 8.1 does not have an automatic save feature like AutoCAD. It does have an automatic save reminder feature, which can be set to as short a time period as 15 minutes. This will pop up a message box to ask you to save your Revit Project.
The place to set this is under the Settings pull-down menu > Options > General tab - Notifications area "Save reminder interval:"
Mel Persin, AIA