The reason there are so many after-Christmas sales is not that retailers harbor a perverse desire to drive the rest of us crazy by offering us at half price items we've already bought. The curious time warp -- three days ago I needed it and couldn't afford it, today I no longer need it and now I could afford it -- is strictly a matter of merchandising exigency.

If you're the type of redoubtable person who emerges from the winter solstice holidays with a wad of cash and the spirit intact, there are bargains to be had. After Christmas, for a number of reasons, it's a buyer's market.

In ordinary years the announcement of these bargains on the 26th of December follows like night after day. This year, some stores report, things are a little askew. Many stores offered substantial reductions before Christmas on some of the most desirable items of the season. Expensive electric coffee makers are a good example. These were not only discounted heavily but offered with sets of cups, coffee grinders and rebates, too. Food processors have also been relatively cheap lately. Cuisinart processors were being sold before Christmas at just about their cost to the retailer, and for the most part remain at that level.

After-Christmas sales break down into two types, mainly along big store-little store lines. Smaller stores need to sell their inventory soon after the first of the year in order to make their cash available for buying spring and summer merchandise. And most stores try to clear out the things that have been around since their last semiyearly purchasing spree because they don't like trying to sell merchandise that's been sitting around for months.

What will be on sale in these stores, therefore, is unpredictable because it depends on what the store finds itself with too much of when the Christmas dust clears. This is often perfectly good merchandise that either the store buyer overbought, or which for reasons having to do with the winds of fashion didn't catch on with the public at large. Savings will probably be greatest at those stores with merchandising strategies that depend most heavily on always stocking the latest thing.

And every now and then a retailer decides to abandon a whole line of merchandise, or a manufacturer discontinues a line. These are sometimes popular items that for one reason or another don't fit the merchandising scheme of a particular store. This is the time of year that these items go on sale. One retailer cites the year she decided Le Creuset just wasn't right for her store. She sold her whole inventory of these pots and pans at 60 percent off.

One category in which you are sure to find spectacular bargains, of course, is the Thanksgiving-Christmas category. Take turkey platters, for instance. As one retailer says, people stop thinking about turkey as soon as Christmas is over, and they don't think about it again until the next Thanksgiving. Look also for turkey accoutrements such as basters, and for anything with Santa Claus on it.

Bakeware associated with Christmas is also usually heavily discounted after the fact. Cookie cutters are usually even cheaper than usual, and so are things like pudding molds, fancy cake tins and candy molds. Serving dishes, mugs and candlesticks associated with the holidays usually go on sale. But small appliances that don't have any spectacular model change from year to year are not apt to be discounted any more than usual after Christmas.

Think also of food. The little containers of glace'ed fruits that haunt fruitcakes and plum puddings keep well from year to year -- some would say from decade to decade -- and are always available after Christmas at substantial discounts. Some kitchenware stores make up baskets of nonperishable specialty foods that don't sell before the holidays, and these too will be on sale.

Some stores import items for Christmas that could only be described as "cute," but that don't necessarily bear a direct connection to the holiday. These are sometimes available after it's all over at prices low enough to make them interesting.

Any appliance that changes in an obvious way with the model year will probably go on sale after Christmas. Microwave ovens, for instance, can usually be bought at their best prices of the year in the weeks after Christmas.

Department stores have a somewhat different set of exigencies affecting what they put on sale. Big volume is more important to a big retailer, so in order to keep traffic up, department stores often discount in January some of the things people most want to buy. These might include microwave accessories -- because everybody who got a microwave for Christmas is out looking for special utensils to go with it. Pots and pans, either in sets or singly, are also apt to be discounted after Christmas. Look also for baking equipment. The big stores will let you know what's on sale with newspaper ads.

One final piece of advice. If you're buying, wait until two days after Christmas. The first day after Christmas the stores are clogged with people returning things they didn't like.