Some customers might look at their staging folders with several GB, and wonder if this is normal. I guess normal depends on how many GBs is several GBs, and how big you
configured your staging folders to be :)

You may have a few GB in your staging folder even with nothing backlogged. The reason is, staging cleanup is only called when the size of a staging folder is over 90 percent of the configured capacity. If the size of a staging folder is below 90 percent of configured capacity (the high watermark), then staged files are kept in the folder and can be used in case new members are added.

So if your configured your staging folder to be 10 GB, staging cleanup will be called after the staging folder size exceeds 9 GB. With several staging folders, you can have each of them at 90% capacity and it can consume considerable space.

If free disk space is a concern, you might need to configure the staging quota to be lower than the default quota when several replicated folders share staging space on the same volume. This ensures that staging cleanup is triggered.

Please read the following article for performance and other concerns when changing stating folder size:
http://technet2.microsoft.com/windowsserver/en/library/ac28a17f-a5ad-42f2-aa3c-d9150d0dbb151033.mspx?mfr=true

More resources:

http://blogs.technet.com/filecab/archive/2006/03/20/422544.aspx
http://blogs.technet.com/filecab/archive/tags/DFS+Replication/default.aspx

--Malu Menezes