I often get 3-4 places to photograph for a magazine. Sometimes they are not billed at the same time and have to be held back for the next month. I get confused on which jobs Ive billed and which ones I haven’t. This is especially true for the lower paying jobs, the High dollar ones I usually remember and bill first. Anyway I found it very helpful for my organization to add the invoice number, (from QuickBooks) to the project folder name. For example 01-10-13 PHG Rugs i2305 refers to “job date Phx Home & Garden Navajo Rugs invoice 2305” I can easily see if I have forgotten to bill something.
If there is no incoice number, then it hasn’t been billed!