Avoiding late fees at all costs

After completing and submitting an invoice for a small project, I had become increasingly annoyed with the client since payment was well over a month past due, and I really needed to get the account settled by the end on the month.

Monday:
Me: “I will need to add a $15 late fee to your account if the balance isn’t settled by the end of the month (next week).”

Client: “I understand. I promise that I will put a cheque in the mail today.”

Thursday:
I figure the cheque should have been here by now, since he lives and works in the same city as I do. After checking my mailbox and still not finding a check. I decided to send the client an e-mail to remind him of his promise, and that I would add a $15 late fee to the balance if I didn’t receive a check by following week.

Friday:
The next day, I received a FedEx overnight envelope with the check for the full amount. The shipping label showed the postage cost: $15.95