The key difference is we don't run a strategy of these key items that we buy thousands of and that we mark down to these low, low amounts

The conventional wisdom is that the most stupendous bargains of the year are to be had on the Friday after Thanksgiving. But the marketplace has become so packed on that crowded shopping day that some retailers are shifting their strategy.

Deals on certain products are likely to be just as good, perhaps even better, in the days and weeks after Friday. In this economy, retailers need to stand out--and some of them are betting they can do so by offering bargains later in the season. Also, while chains are not discounting as deeply as last year, they know the primary way to get penny-pinching consumers to spend is to keep the deals coming all season long.

Exactly which strategy retailers are pursuing this year differs not only among shopping chains but among categories of merchandise. That means the best time to shop for the season could hinge on which items are on your list.

"Black Friday is about cheap stuff at cheap prices," said Daniel de Grandpre, the editor in chief of DealNews.com, which tracks such sales each year. "That means that high-end stuff is not on sale on Black Friday. It just isn't."

That is not to say consumers who brave the nation's stores on Friday will not find deals on flat-screen televisions and fluffy ear muffs. But the products on sale that day, particularly electronics, generally are lower-end products without many extras, or they are older models on the verge of being discontinued. That is, of course, a reason stores are able to offer them at low prices.

"It looks like a real mixed bag of deals and duds," said Andrew Eisner, director of content for Retrevo, a Web site that reviews consumer electronics and recommends where and when to buy them.

Many of the gadgets on sale this Friday will be outdated models, he said, like navigation devices without speech capability, Blu-ray players without Internet connections, and digital cameras without face-recognition technology.

Manish Rathi, a co-founder of Retrevo, cited some "over-the-hill" products, like a Nikon CoolPix digital camera being sold at Target for $88, reduced from $140.

De Grandpre said luxury retailers tend to stay out of the Black Friday fray because they would rather not associate with bargain-basement shopping. To participate in the nation's uber-shopping day in a way that is befitting their status, luxury chains do offer deals, but only in certain popular holiday and seasonal categories, like coats and home decor. And they do not bother to open at 5 a.m., a common opening time on the day after Thanksgiving for the lower-end retailers known as big-box stores.

The luxury chain Saks, for instance, is offering 40 percent off already reduced merchandise, but not its newest collections. The chain does not bring in merchandise specifically for the day after Thanksgiving. And the doors open at the relatively late hour of 8 a.m.

"The key difference is we don't run a strategy of these key items that we buy thousands of and that we mark down to these low, low amounts," said Kimberly Grabel, senior vice president for marketing at Saks. "That is the big-box mentality."

Stores have greatly reduced their inventories since last year, when the economic downturn forced them into panic selling. So while there will be sales, as there are every year in any economy, it is possible stores might run out of certain products or sizes. "For the best selection you are going to need to shop early this year," Grabel said.

Her best advice? "Stay home and shop online."