My little 7 year old puppy mill bichon has lived with me for a year now. In that time she had bladder stones and although didn't need an operation, had lots of xrays and urine tests. The insurance paid out without any problems.
Sadly Poppy has now been diagnosed with the start of cataracts in both eyes.
As each eye will cost around £3,000, I am glad that I have her insured.
I would definitely say have your dogs insured, specailly if they are young.