> when the device fails in whatever way
It's still not that simple.
It's not like you get six years of unlimited state-mandated insurance. The 'six years' is just from the statute of limitations -- it's just the limit after which you can no longer do anything about a violation of a contract of sale. [0]
But there still has to be violation of the contract of sale. Which means it only applies to defective products. (Or ones not as described, not fit for their purpose, etc.)
So eg it doesn't apply to accidental damage. If you spill coffee on your shiny laptop, consumer law won't help you, even if you only bought it ten minutes ago (unless the product was sold as waterproof, ofc). It also doesn't apply to normal wear and tear, unless you can argue that the degree to which it's deteriorated is enough to imply that the goods weren't of satisfactory quality at the time they were sold, taking into account the context of the kind of good, how it was described, the price, etc.[1]. And so on.
Until six months, the burden of proof is on the retailer to show that anything that goes wrong with the product was not due to the product being defective. (I.e. if there's a problem, and there's no obvious cause, there's an assumption that the goods are faulty). After six months, that assumption is reversed, and the burden is on you to show that the product was defective.[2]
We have pretty good consumer protection in the UK, but it's not a replacement for insurance (e.g. applecare etc). (Whether you actually need insurance for a laptop purchase is another question. Generally if you could replace a thing without too much hardship, insurance is pointless -- the expected value is negative (ie Apple makes a profit on Applecare); you're purchasing a reduction in variance).
(IANAL, just interested in consumer law)
[0] http://www.legislation.gov.uk/ukpga/1980/58/section/5
[1] http://www.legislation.gov.uk/ukpga/2015/15/section/9
[2] http://www.legislation.gov.uk/ukpga/2015/15/section/19