How much to spend on advertising is always problematic. Some companies use the comparative-parity method – they simply match their competitors’ spending, thereby avoiding advertising wars. Others set their ad budget at a certain percentage of current sales revenue. But both these methods disregard the fact that increased ad spending or counter-cyclical advertising can increase current sales. On the other hand, excessive advertising is counter-productive because after too many exposures people tend to stop noticing ads, or begin to find them irritating. And once the most promising prospective customers have been reached, there are diminishing returns, i.e. an ever-smaller increase in sales in relation to increased advertising spending.