In some cases, not all. I calculated a 12 month period (maybe about 6 months ago) and I spent about £2,000 on premiums and made claims worth £3,500... so insuring was definitely worth it for me. Every year that I've had insurance (approx. 6) I've come out better off with insurance.
My biggest bills have been:
Artie - Bladder surgery (cystotomy) £336; kidney stone removal £800; Kidney removal £600. Ongoing treatment for bladder sludge c £400 a year for 4 years.
Elijah, surgery for blockage c£800. Many episodes of stasis (obstructions) up to £1000 in 12 month period.
Gracie, surgery for blockage c£700
Binky, investigative surgery and supportive care for unknown ... turned out to be pancreatitis (he died of it).
Erin, Dental abscess initial treatment apx £400 plus ongoing cover for dentals as a result of the tooth extraction.
They are just a few examples.