Every freelancer knows the invoice that goes into the void.

You did the work. You sent the PDF. "Net 30" in the footer like it means something. Day 31 comes and goes. Now there's $4,250 sitting in someone else's account, and the only way to get it is to write the email you least want to write — the one where you chase your own money and try not to sound desperate. So you don't. You tell yourself you'll do it Monday. Monday you find something else to do.

The tedious part isn't writing one reminder. It's that the right moment to send it is different for every client, and you have no idea what it is.

Net-30 is a lie your accounting software tells you

Here's the thing I learned staring at a spreadsheet of paid invoices: the due date has almost nothing to do with when people pay.