Are extended warranties worth it?
That's a very difficult question to give a universally correct answer to, becasue it very much depends on the product involved, the individual's situation, and on what is and isn't covered in the warranty policy.
As Otherclive has commented his policy was of no use for the problems he had.
Strictly you do not need extended warranties, becasue your statutory rights as described in the Consumer Rights Act (CRA) provides you with a potentially powerful set of remedies, BUT: whereas with an extended warranty, the types of failure are well defined and if your product fails within one of their categories its usually fairly straight forward to get the product repaired, replaced or refunded depending on T&C's of the policy.
By comparison the CRA for failures after the first 6months you do have to be able to show the the fault was due to particular types of failure.
Often the suggestion that a customer will use the CRA will be enough encouragement to get the seller to accede to repair or refund as appropriate without having to actually formally start proceedings.
The CRA costs nothing, and can have effect up to 6 years (5 years in Scotland) which is often better than the combination of the normal manufacturers warranty and extended warranty combined.