The biggest shake-up of consumer law in a generation comes into effect today to strengthen, clarify and modernise protection for shoppers.
The new Consumer Rights Act guarantees shoppers a full refund up to 30 days after buying a faulty item, provides protection for digital purchases for the first time and cracks down on unfair terms in contracts.
Shoppers now have 30 days to reject a faulty item and demand a full refund, clarifying previously unclear rules on how long this period should last.
After 30 days, retailers have one opportunity to repair or replace a faulty item, at the customer's choosing.
If the attempt at a repair or replacement is unsuccessful, the consumer can then claim a refund or a price reduction if they want to keep the product.
The new act also extends clear legal rights to digital purchases, giving consumers the right to a repair or replacement for faulty downloaded or streamed content such as apps, music, movies, games or e-books.
Another change makes it easier for shoppers to challenge hidden fees and charges, preventing companies from enforcing terms if they are deemed to be unfair - even if they are written in plain language.
In the case of a dispute, certified Alternative Dispute Resolution providers are now available to help as a quicker and cheaper alternative to going through the courts.
UK consumers spend £90 billion a month but figures from the Department for Business, Innovation and Skills (BIS) show shoppers encountered more than 18 million problems with consumer goods and services in the 12 months to the middle of last year, leaving them £4.15 billion out of pocket.
BIS said the new act will make it easier for consumers to know their rights and shop with confidence by streamlining eight pieces of legislation into one.
Business minister Nick Boles said: "Whether it's downloading music or buying a fridge freezer, the Consumer Rights Act makes it easier to understand your rights.
"These changes will also simplify the law for businesses so they can spend less time worrying about unclear and unwieldy regulations."
Which? executive director Richard Lloyd said: "Consumer law was crying out to be brought up to date to cope with the requirements and demands of today's shoppers.
"Getting a refund or repair, dealing with issues with faulty digital downloads and understanding contracts should now all be much simpler.
"Businesses must ensure their staff are aware of the changes so they're not caught out short-changing customers or breaking the law."
Citizens Advice chief executive Gillian Guy said: "Clear consumer rights are good for shoppers and businesses.
"Businesses have a real opportunity to show they value their customers by upholding their new rights and signing up to an alternative dispute resolution scheme."