1. Not having an effective backup system. This should be obvious, but even so many companies have no practical backup of their invoicing. The best backup isn't another PC in your office -- a fire or theft can eliminate any advantage you thought you had on that front. Instead, the best invoicing system backs up online. To the cloud, as it were.
2. Only having a single gatekeeper. Does Emily do all your invoicing? That probably works fine most of the time, but what happens when she's sick, on vacation, or otherwise busy? What happens when she quits? Make sure there are several people who understand your system and can step in as needed.
3. Using snail mail. You don't really still put paper invoices in the mail, do you? Not only is it slow, there's no way to verify receipt without paying extra.
4. Forgetting to invoice. This doesn't ever really happen, does it? Of course it does -- especially if you're still manually processing invoices rather than using an automated system that can manage invoices over the lifecycle of your project.
5. Currency conversion glitches. If you bill internationally, it's easy to miscalculate your currency conversion, which can lead to delays or under-charges.
6. Sending the wrong invoice. This is possibly the scariest thing that can go wrong in your invoicing chain. Sending the wrong invoice to a customer (or the right invoice to the wrong customer) is deeply embarrassing. But it also shows your hand; it reveals your rates and terms and other confidential information.
7. Sending dupes. Accidentally re-using an invoice number can cause all sorts of frustrating and time-consuming accounting problems, both for you and your invoicee.
Personally, I have encountered each and every one of these problems from both sides of the invoice, and from companies large enough to know better. What's the worst invoicing blunder you've seen happen? Sound off in the comments!
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