Put your payment terms right on the invoice itself. Net 15 or Net 30, whatever you use. Then add a line about late fees if they go past that date.
I also send a quick email when I attach the invoice. Something like ‘Invoice attached, payment due by [date].’ Makes it harder for them to claim they missed it.
The key is being consistent. Same terms, same format, every time. Clients get used to your process and pay faster.
I learned this the hard way after too many late payments.
Now I call out the payment date in the subject line of my email. Something like “Invoice #123 - Due March 15th” so they see it right away.
Inside the invoice, I put the due date in bigger text near the top. Not huge, just noticeable. And I always include what happens after 30 days overdue - usually a service pause or late fee.
The thing that helped most was sending a friendly reminder 3 days before it’s due. Just a quick “Hey, invoice due this Friday” message. Catches the ones who genuinely forgot and saves you from chasing them later.
Most clients aren’t trying to be difficult. They just have their own cash flow issues or honestly lose track of dates.