The responses were interesting.
Some thought that you never offer discounts/promotions to loyal customers because you give up precious gross margin dollars.
Some thought that you never offer discounts/promotions to prospects because that isn't fair to loyal customers paying full price.
Nobody offered actual customer data from Customer Development work that proved what you should and should not do.
Think carefully about your discounting efforts in terms of Customer Development. There are few things that marketers can muck up more than the development of customers by treating some better than others.