Presidents Day is a time to reflect on the giants. Lincoln. Jefferson. Washington. And of course, mattress sales. "You go hunting when the ducks are flying," says Kevin Damewood, the executive vice president of sales and marketing at Kingsdown, a mattress manufacturer. He says three-day weekends are when people have time to shop for a new mattress. It's also when many people decide to move, and consequently when many people are in the market for a new mattress. Yet despite the flashy advertisements, mattress shopping can be met with the same level of excitement as buying new tires. "A mattress has often been considered what you might call a grudge purchase," says Mary Helen Rogers, the vice president of sales and marketing at the Better Sleep Council, a part of the International Sleep Products Association, which represents the mattress industry. A new survey from the Better Sleep Council, however, suggests this is starting to change. It found consumers were replacing their mattresses