By now, the January hangover has well and truly set in. The month-long December party has left many a bank account, kitchen cupboard and Jack Daniels bottle empty, and the next pay-cheque seems but on a distant horizon. Invariably there’re a few bills that are mistakenly or not-so-mistakenly overlooked. Which may suit you if you’re the debtor. But if you’re the creditor, what do you do? For the umpteenth time, you are the one left juggling your cash flow because your debtor has unilaterally decided to delay payment. At this point you may be seriously contemplating charging interest on overdue accounts. Adding interest onto outstanding balances can be a good way of forcing a debtor to pay on time. But before you do so, there are a few things you should be aware of.