I have a small in home business and this item has made my filing so much easier. I'll transfer into folders at the end of each month and reuse this for the next months clients!
We use these to organize the open invoices for our mid-size electrical firm as well as open proposals. They make tracking very easy and accessable. No more rummaging through a "bulk" folder or pulling individual account folders.
This is a really practical daily organiser. It does get bulky as it fills up so its has to be used as a temporary file and then its contents moved to permanent filing storage.