I haven't used an invoice. Our clients pay a deposit/retainer when they sign our contract, and I send them an informal reminder e-mail around 38 weeks rather than an invoice. Just an FYI on what works for me and my partners.
I do the same thing as JessicaE. I have it in my contract that they pay a small deposit at the signing of the contract to retain my services. The rest is due at the final prenatal appointment (around 38 weeks). I find it's easier than trying to collect after the birth.
Yeah i personally dont use an invoice either, unless requested by a client. But I coordinate a collective of local doulas who sometimes work for moms who are funded by the collective. So the doulas, in those cases, would invoice the collective for the money owed to them. We need it formal because of how we're funded....
I've googled for this but haven't come up with anything useful...
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