What every invoice must contain
Missing information is the most common reason an invoice sits unpaid: it lands in an accounts-payable inbox, fails a validation check, and nobody tells you. Include all of this every time, even for a client you've worked with for years.
- A unique, sequential invoice number — gaps and duplicates cause rejections.
- Issue date and a specific due date, written as a date, not as 'net 30'.
- Your legal business name, address, and tax/VAT number where applicable.
- The client's legal entity name — not the contact's personal name.
- A line-item breakdown: what was done, quantity, unit price, line total.
- Subtotal, tax applied, and the total due in a clearly stated currency.
- Payment methods and full bank details.
- Any purchase-order or reference number the client asked for.
Payment terms, and which ones work
Net 30 is the default in most industries, meaning payment is due 30 days from the invoice date. Net 14 is realistic for smaller clients and freelancers. Net 60 and Net 90 exist mainly because large companies can impose them, and you should price for the financing cost if you accept them.
Two changes reliably shorten payment time. First, write the actual due date — '15 September 2026' rather than 'Net 30', because the second requires the reader to do arithmetic and they won't. Second, invoice the day the work is delivered, not at the end of the month. A single day of delay in issuing is a day of delay in being paid, and monthly batching adds up to two weeks of average lag for free.
Get paid before you start, sometimes
For a new client, a large project, or anything with material upfront cost, take a deposit — 30 to 50% before work begins is standard and rarely challenged. It filters out clients who were never going to pay, and it means a walked-away project doesn't cost you the whole engagement.
For ongoing work, milestone invoicing beats a single invoice at the end. It smooths your cash flow and it caps your exposure: at any moment you're owed for one milestone rather than the entire project.
Chase early, briefly, and without apology
Most late payments aren't refusals — the invoice was missed, the approver was away, it needed a PO number nobody mentioned. Assume that, and the chase becomes administrative rather than confrontational.
A schedule that works: a short reminder three days before the due date; a direct email the day after it passes; a phone call at day seven with the accounts department rather than your usual contact; a formal notice referencing your late-payment terms at day fourteen. Keep each message two sentences and attach the invoice again — you're removing excuses, not making a case.
Track what you're owed, not just what you've earned
Revenue recorded is not money received. The number that matters for survival is outstanding receivables — the total sitting in unpaid invoices — and its age profile. Ninety days of receivables that are all under two weeks old is a healthy business; the same total where half is over sixty days is a business with a collection problem it hasn't admitted to.
Track invoice status explicitly: draft, sent, partially paid, paid, overdue. IncomeWise's Business workspace does this per client and logs the revenue automatically when an invoice is first marked paid, so the P&L reflects cash received rather than hopes issued.
When an invoice won't be paid
After a formal notice, escalate in proportion to the amount. Small sums: stop work, keep the relationship, write it off if chasing costs more than the debt. Larger sums: a solicitor's letter is inexpensive and resolves a surprising share of disputes on its own. Beyond that, small-claims processes exist in most jurisdictions and are designed to be used without representation.
The real lesson is upstream. A client who doesn't pay the deposit rarely pays the balance — and the cheapest debt to collect is the one you declined to extend.