I wanted to share something I recently learned. Revit files automatically get compressed when the SAVE AS option is used to save your project rather than just the conventional SAVE. This is how is works, take for intance the following file ROOF FRAMING_MODEL.rvt its normal size is 5,080 K. However if I use the SAVE AS function and give this file a new name such as ROOF FRAMING_MODEL_SAVE AS.rvt you will notice that the file size decreased to 4,440K. This is almost 15% smaller. At this point you can then delete you original file and replace it with the new one.
Save As File: