Goods cannot always be expected to work fault-free even those that are more expensive. They can break down through normal use and normally the retailer will provide a suitable remedy.
Consumers cannot expect to hold the seller responsible for “fair wear and tear” the kind of wear that all goods may suffer from. The display from a TV may not be as bright after say three years as when it was new but this would due to normal use.
There needs to be a fault that was present on the day of sale even though it only became apparent later on, or a mis-description of the goods, or a lack of durability that suggests the goods were not of satisfactory quality to start with.