Scenario: a founder sends an invoice, gets busy, and three weeks later realizes it was never followed up on. Client didn't ignore it on purpose: it just slipped, on both sides. This happens constantly, and it's rarely about the client being unreliable. It's about not having a simple system to flag what's outstanding past a certain number of days. Has this happened to you? Comment "yes" and, if you're comfortable, how long it took you to notice.