Bunkering a vessel is an art, and no two voyages are likely to be exactly the same, due to seasonal changes, price fluctuation, and the need to balance fuel prices against freight income. It can sometimes be more financially beneficial to take less cargo in a port where bunkers are cheap and to fill up with bunkers instead. One must also take into consideration limitations imposed by loadlines against the need or desirability to take bunkers en route. At first glance, it may seen advantageous to call frequently at bunkering ports to shorten the intermediate steaming time and bunker quantity requirements, thereby maximising cargo intake. But no shipowner willingly puts into port unless absolutely necessary, because of the extra time, risk and expense involved. ‘A ship earns money only when laden and at sea’ is a very accurate maxim. However, in this era of wildly fluctuating bunker prices, often purely as a result of unexpected political decisions rather than because of discernable economic trends, bunker programming is not the straightforward task one might otherwise expect. The best advice in practice, is to obtain representative prices en route if time permits, otherwise to base the estimate on the price and quantity required at the loading port and to treat cheaper bunkers discovered later in the voyage as a bonus. Where a vessel is likely to spend some time in port where bunkers are difficult and/or expensive to obtain, it is essential to pre-plan your strategy and to arrive with sufficient quantity on board. Safety surplus quantity will be needed and the amount required for this purpose will need to be judged by experience and knowledge of the conditions likely to be encountered and the availability en route of alternative bunker supplies.