Most appliance insurance policies include cover for:
Parts, labour and call out charges
Each policy will have things it does not cover, like cosmetic damage or electrical white goods over a certain age. Check the policy documents once you have your quotes, to make sure you get the cover you need.
Work out how much your appliance would cost to replace. If it's less than the cost of an extended warranty, you could be wasting your money.
However, most policies include replacement cover if your appliance cannot be repaired. This could save you money if your appliance is not under the manufacturer's guarantee.