That's because the biggest sales on a variety of consumer goods often correspond with product launches at industry trade shows, just as some tend to be tied to particular seasonal promotional events.
Here's a primer on the best time to land deals on a range of big-ticket products.
Retailers tend to hold the biggest mattress sales during the "patriotic holidays," such as Memorial Day, Fourth of July and President's Day, says Karin Mahoney, director of communications for the International Sleep Products Association.
"I don't know why ... but that's when retailers -- from Macy's to Sleepy's -- have the most heavily discounted sales," Mahoney says. Indeed, you can shave $100 or more off the mattress price during these red-white-and-blue sales, she says.
When buying a mattress, it's also important to note that it's one of the few products for which you can haggle down the price in a chain store -- so make sure to do just that, says Christine Frietchen, editor-in-chief of ConsumerSearch.com, a product review aggregator that compares ratings from experts and user reviews.
"And if a sales associate won't give you extra money off, ask them what they can throw in for free with your mattress, like a box spring," she says. "It's definitely one of those products where you should ask what else they can do for you."
In the market for a new car? Shop over the summer to snatch up optimum deals, says Jeff Schuster, executive director of forecasting for J.D. Power.
The savings can be anywhere from $500 to $3,000 for cars that are less in demand, such as gas guzzlers like pickup trucks, Schuster says.
It also pays to time your car purchase around the automobile shows, which are held at different times in cities throughout the country, such as Detroit, Los Angeles, New York and San Antonio, Schuster says.
"Around the time of the auto shows, car manufacturers will offer special deals to entice buyers to purchase and to draw attention to the show, like, 'Here's a special show savings: Take an extra $500 off.'"
3. Consumer Electronics
The annual International Consumer Electronics Show, where manufacturers unveil the latest and greatest new products headed for stores, is held in January.
So a "sweet time" to buy big-ticket electronics such as flat-screen televisions, Blu-ray players and digital cameras is between January and March, as "retailers are trying to clear out old inventory to make way for new inventory" that debuted at CES, Frietchen says.
Around the time of the Super Bowl last year, for example, "We saw 40-inch LCD televisions for as low as $300, and 32-inch televisions for $200 -- 40% off normal selling prices," Frietchen says.
4. Washers and Dryers
Black Friday weekend, the Super Bowl of shopping, is not just for finding holiday presents.
"You can get as much as 50% off washers and dryers around Black Friday," says Carolyn Forte, director of the home appliances and cleaning products department of The Good Housekeeping Research Institute.
"Don't just stick to what you need for gifts during Black Friday -- think a little outside the box," she says.
Shop for laptop computers in April and during back-to-school sales, which will save you 20% to 35%, Frietchen says.
That's when "fully-functional" laptops in the 15-inch range can be had for as low as $250, she says.
Big discounts can also be found whenever Microsoft (MSFT) releases a new Windows operating system. "Windows 8, for example, is expected to be shipping in new laptops by Christmas, so the holidays this year should be an especially good time to pick up Windows 7 laptops at steep discounts," Frietchen says.