Huge reclaimable space with Windows 8 VM

I have a Windows 8 64-bit VM running in Fusion on my MacBook. Since installing it back in October I have had to frequently, almost once a month, clean up the VM to recover reclaimable space. I never had to do this with the Windows Vista or Windows 7 VMs I had previously. Admittedly, my MacBook is low on disk space, but it seems as though Windows 8 is eating through more disk space than previous versions of Windows. If anyone can enlighten me as to what might be going on that would be great. Then again, it could just be the minimal disk space!