Solidworks Users: Any Obscure Locations to Make Sure To Get When Backing Up Your Data Set?

A friend works at a small engineering firm.
His boss has asked for help with backing up all of the engineering workstations so that he won’t lose any work in case of disk failure.
He, in turn, asked me for advice.
Now, I know how to back up Word, Access, Powerpoint, etc files using the typical backup software solutions.
I assume that SolidWorks projects consist of a variety of files with a few different extensions.
Would these typically be stored in a single folder or set of subfolders of one?
Are there any weird gotchas? A metadata file in a weird directory?
Thanks in advance!