My vets first question is always 'are you insured'? This shouldn't make a difference to treatment which makes me think if you are insured they will look at more costly treatment which ends up pushing up the cost of insurance premiums
My vet asked me that when my dog needed some fairly complex surgery. She wasn't insured, and I was pleasantly surprised when the bill was only £500 odd.
When I went to one of the follow-up appointments, we saw the newly qualified vet who'd assisted at the surgery. She was talking about what an amazing job the vet had done, and said that the operation took 3.5 hours.
I came home and checked the bill. Lovely vet had only charged me for 45 minutes of surgical time!
I changed vets a few years ago, because I was unhappy with the old one. The previous vet was purely small animals and equine, they didn't do any farm work. The new vet has a large agricultural practice and their fees are much lower than the previous one. I wonder if there is a connection?
Re insurance, I put a sum equivalent to the insurance premiums in a savings account every month, and use it to pay the bills. My first dog got through his whole 17 years without a single claimable event, my second would have had 2 small bills where I could have claimed, and even with the £800 bill for current dog's surgery and the cost of having her spayed, there is still £2,200 left in that account. (I have made large withdrawals when each of the previous dogs died, so that's built up over 12 years).