The short version: escalate in stages (reminder, firm follow-up, formal notice, final notice) on a fixed schedule, get every promise in writing, and stop new work once a formal notice is ignored. Most invoices get paid in the first two stages; the playbook below is for all of them.
Why do clients pay late?
Three reasons, in order of frequency: they forgot (most common, solved by a nudge), they're managing their own cash flow at your expense (solved by firm, consistent follow-up that makes you the squeakiest wheel), and they can't or won't pay (rare, solved by payment plans, work stoppage, or collections). Your process needs to handle all three without you guessing which one you're facing.
Stage 1: The systematic reminder ladder (day 0-30)
Use a fixed schedule (due date, +7, +14/21, +30) with escalating formality. We keep full copy-paste templates for each stage here: payment reminder email templates.
Two rules that matter more than the wording:
Never skip a step, never delay one. Clients learn whether your invoices can be ignored. Consistency is the message.
Always ask for a date. "When can I expect payment?" converts a vague situation into a commitment you can follow up on the day after it's missed.
Stage 2: When they promise and don't deliver
"I'll pay Friday" is progress, if you track it. Log the promise, and follow up the morning after it's broken, referencing it directly: "You mentioned payment would go out Friday. It hasn't arrived. What happened?" A broken promise referenced politely is one of the strongest levers you have; it makes the next delay socially expensive.
Stage 3: Make it easier to pay than to stall
Payment link in every reminder. Every click you remove increases collection speed.
Offer a split. For larger invoices, "would it help to split this into two payments?" recovers money that a hard demand won't. Half now beats zero indefinitely.
Late fees, only if they're in your terms. 1-1.5%/month is typical. The fee itself rarely matters; citing it changes the tone of the conversation.
Stage 4: Stop work
Once a formal notice (week 2-3) is ignored, pause all current work and say so plainly: "I've paused work on [project] until invoice [#1234] is settled." This is not aggressive; delivering new work while unpaid tells the client the invoice is optional. Put a stop-work clause in your contract so this is expected, not a surprise.
Stage 5: Collections, small claims, or letting go
At 60-90 days with no response: a collections agency (they typically take 25-50%), small-claims court (worth it for larger amounts in your jurisdiction), or a written-off invoice and a fired client. Do the math coldly: sometimes the $400 invoice isn't worth ten more hours of your life, but the process that prevents the next one always is.
Prevention: the terms that make this rare
Experienced freelancers converge on the same setup: deposit up front (30-50%, work doesn't start without it), short terms (net 7 or net 14; net 30 is a corporate convention, not a law), late fees in the contract, and systematic follow-up from day one.
That last one is what DunPilot automates: it tracks who owes you, drafts each reminder in the right tone for that client's history, tracks their promises, and shows you exactly how much it recovered. You approve every email; it just never forgets, never delays, and never feels awkward on your behalf.
Tired of chasing invoices by hand?
DunPilot finds your overdue invoices and drafts reminders tuned to each client's payment history. Nothing sends until you approve.