I am in 2 minds with this because I had a dog get to old age and she never had any issues until the last year of her life and the vet bills we paid out were far less than we would have paid over the life of her insurance.
However I also have 3 cats now and in the past year ive put in claims of in excess of £5k and also £3k+ of out of pocket expenses because I made the stupid decision to have 1 uninsured for 2 months until the other two were due for renewal, to do their insurance all together for ease. During those 2 months uninsured he had a sore, that required a blood test due to not healing which showed slight anemia. He then went on a year later to develop an auto immune illness which is around anemia so these treatments are ongoing for life and not covered. This had a knock on effect of affecting his heart, which luckily was covered.
So while most of the time you might be ok, as soon as something happens, those bills can go up eye wateringly fast.
I think the most important question to ask yourself, if your cat suddenly needed major investigations could you afford it? Would you be willing to pay it?
One of my other cats is currently having some issues and may require a CT scan, im not sure of the exact cost but it would be over £1k, he also had to have a tooth extraction and that was £500.
Its a gamble either way, we took the gamble with my cat on the basis it was only 2 months, he was young and we could use savings for any problems but it was stupid and will cost us a lot over his lifetime as he is young but it was us that took the risk.
Knowing ive had pets that have gone all the way to old age and cost very little and also pets that cost a lot in a short space of time, I think for me I would always opt for insurance now seeing how fast the bills can go up.
Just to keep in mind, maine coons (my youngest is a maine coon) are at higher risk of heart issues and teeth is also something to consider in later life especially and the surgery can become a little more complex if needed. Any heart issues would come with scans to diagnose and then multiple medications to control.
If you do go for insurance, shop around. Everyone recommended petplan to us but we are with LV for our car insurance so went with them, they offered a discount as we have both insurances together and they have been great to deal with as we have had claims both for the car and the cats in the past year (with both, we have taken out far more than we paid in) and I will say I expected my insurance to massively go up this year after the claims but it didnt really go up by much at all.