Unfortunately, unwary shoppers can be caught out and can find they have bought an item that someone else has used.
It is illegal for a retailer to sell something as new that they know is used - and that applies to goods returned by customers as well as equipment they have traded in or part-exchanged.
But not all shops follow the rules. Paul Cooper is a divisional manager with West Yorkshire trading standards. His team deals with some 30,000 complaints a year concerning consumer goods. Mr Cooper's files include portable computers sold as new that contained previous owners' data; video recorders marked with other buyers' postcodes, and even an answering machine with the original purchaser's message (and eight messages from callers) still on the tape.
If trading standards suspect deliberate deception, they will prosecute. There is no reason why shops cannot sell used or returned goods - the point is that shoppers should know what they are buying. A visitor to a second-hand specialist knows what they are taking on; someone who visits a high-street store or out-of-town superstore will expect what they buy to be new. Some retailers use terms such as "graded" or "ex-display" to cover goods which have slight cosmetic damage, missing packaging or which have genuinely been on display on the shelves.
"If I saw something that said 'manufacturer's special', 're-manufactured', 'reworked', 'graded' or something along those lines, I would regard it as a warning," says Mr Cooper.
Retailers specialising in discounted electrical goods stress that shops should tell customers why they are being offered a keen price - before they hand over any money.
An independent hi-fi chain, Richer Sounds, stocks new equipment, ex-display and clearance items, second-hand goods brought in through the company's part exchange programme, and "factory repack" items.
"Factory repack products are products that are ex-display or repaired, or they may be mail-order returns," explains David Robinson, managing director. "They are either refurbished by the manufacturer, or by us. It allows us to discount them. But it is made very clear and we go to great pains to make it very clear."
Superficial damage might not affect the way a product works, and buyers are still protected if it breaks down.
"If you buy graded, it is perfectly clear that you are buying an imperfect item. It has nothing to do with the mechanical condition," says Paul Cooper. "If you buy something with a damaged case and the case deteriorates, there is nothing you can do. But if it does not work, you can expect the same treatment as with a new item."
The buyer's ultimate sanction is to reject the equipment, by returning it to the store. This is hardly the most convenient solution. The easiest approach is to ask searching questions before buying graded or ex-display items. Store staff are under no obligation to volunteer a product's history, but if you ask, they must tell the truth.
the knowledge: 'new' or second hand
New means new. If you buy something that is supposed to be new, and it has been used before, take it back and demand a refund.
Stores use a number of terms to describe less-than-perfect goods. Better retailers show the reason for a discount on the label. If they do not, ask why the product is cheaper. It may even be possible to negotiate more off the asking price.
Second-hand goods offer far less protection to consumers. To play safe, buy from a reputable shop offering a warranty. An authorised dealer for the brand usually has the best support and repair facilities.
Cosmetic damage means just that. The product should be in full working order, ideally with a full guarantee.
If you encounter problems or think you have been deceived, contact the local trading standards office and make a complaint.