Cats don't tend to get ill?
Are you smoking crack, mine get into all kinds of scrapes and mischief, just recently one came home with a load of peck marks on his head (luckily not bad enough to warrant seeing a vet) from where he'd probably tried to have a crow (and he has had one before).
But realistically unless you've got an ultra dosile indoor cat that doesn't hunt your cat will injure itself at some point requiring a visit to the vets, or it'll get ill some other way - abscess, cancer, car accident, broken leg after getting it caught, got the ***** after eating some questionable mouse.
Cats get up to serious mischief, you're insane to not have insurance. I've owned cats for over a decade and I could have easily been put under with how much some of the treatments cost.
I remember a bill in region of £2k after one came home with a big old hole in his neck, my guess a fox attacked him and he managed to either kill the fox or get away, he was a hardy ******* that one, lived to be old as anything.