We always say that a sensible approach to invoicing can help to cut down on the number of problems you face - and that's still true. Chasing up invoices, making sure they've been received by the client, and querying any payments as soon as they become overdue can all help to encourage clients to pay up on time.
But when an invoice goes unpaid, it's easy to find yourself becoming more and more lenient in the hope that your client will eventually pay - while they become less and less reasonable in their reasons for delaying.
Read more: Dear John... Dealing with a (Very) Overdue Invoice