Consumer electronics insurance is often a notorious rip-off, unless it's included in the purchase price a la John Lewis. Even then JL's prices are generally reflective of this extra warranty, unless you can get them to price match.
Let's say for every three TVs you own, one breaks after the manufacturer's warranty has expired. I consider this pessimistic as I don't think I've ever had a TV that's developed a fault past any faults that presented themselves immediately after purchase.
If the three years extra insurance costs you £180 for each TV, you would have saved enough to by a new (and very good) TV by the third purchase had you not purchased the extra insurance. If one of your TVs breaks on day one after the (let's say) two year manufacturer's warranty has expired, then you write off your losses, go down the skip, and go and buy another TV. You're still quids in compared to purchasing extended insurance, as long as your next two TVs last five years fault free.
Of course I'm ignoring the psychological aspect of consumer peace of mind in this and concentrating on probabilities and expected outcomes, but for me the adverse psychology of paying for extra product cover outweighs the concern that it might break.