Most businesses operate on Net 30 terms, meaning payment is expected within 30 days of the invoice date. That’s the standard for most B2B transactions. Some industries move faster with Net 15 or Due on Receipt. Others like construction and government contracts often extend to Net 45 or Net 60.

What counts as “reasonable” really depends on what you communicated upfront. If your invoice says Net 30 and you’re on day 45 with no payment, you’re past reasonable. If you never specified terms, you’re in a gray area where the customer might assume they have more time than you expected.

Here’s how to think about the follow-up timeline. In the first week past due, send a friendly reminder. Most late payments are simple oversight and a quick nudge solves it. Between days 8 and 21, follow up with a phone call or direct email. Make it personal rather than another automated notice. From day 22 to 45, escalate with firmer communication and consider whether this customer is worth continuing to work with. Past 45 days, you need to decide whether to pursue collections, negotiate a payment plan, or write it off.

The bigger question is whether you have a system for tracking what’s owed and following up consistently. Businesses that struggle with collections usually don’t have a routine for monitoring accounts receivable. They send invoices and hope payment shows up.

Running aging reports weekly lets you catch slow payers before they become bad debt. A bookkeeper can pull reports showing exactly which invoices are current, which are 30 days past due, and which need immediate action. Without that visibility, you’re guessing.

If you’re routinely waiting 60 or more days for invoices that were due in 30, the problem isn’t usually the customer. It’s unclear payment terms, weak follow-up, or both. Customer invoicing that goes out promptly with clear terms and consistent follow-up gets paid faster than invoices that drift out whenever someone remembers.

For service businesses and contractors, cash flow depends on collections. Waiting three months for a payment that was due in one can mean scrambling to cover payroll or delaying your own vendor payments. Set clear terms, follow up consistently, and treat overdue invoices as a priority rather than an afterthought.