I have a very precise workflow when saving and archiving our software and I would consider this as a best practice.
1. Save the downloaded [Browser Download] files and store them in a safe location for future use. In this case, I have downloaded the Autodesk 2013 products and placed them in a 2013 folder.
2. Copy the .exe and .rar files to the local workstation and run the installer locally. The default location for extracting the software will be C:\Autodesk folder.
3. I will rarely will copy the AutoCAD_Architecture_2013_English_Win_64Bit folder to a network location or a USB thumb drive because:
a. The size of the files/folders is larger. i.e. 2 GB (compressed) vs 4 GB (uncompressed) for AutoCAD Architecture 2013.
b. There is the potential corruption of the installation of the software as there are 9434 files in AutoCAD Architecture 2013. If one of these files are on a bad sector of the 'external' hard drive, you will be hosed.